Radiology Review Manual
6th Edition

Ear Nose and Throat
Differential Diagnosis of Ear, Nose, and Throat Disorders
Facial nerve paralysis
  • INTRACRANIAL SEGMENT
    • intraaxial
      • brainstem glioma, metastasis, multiple sclerosis, cerebrovascular accident, hemorrhage
        • cranial nerve VI also involved
    • extraaxial
      • CPA tumor (acoustic neuroma, meningioma, epidermoid), CPA inflammation (sarcoidosis, basilar meningitis), vertebrobasilar dolichoectasia, AVM, aneurysm
        • cranial nerve VIII also involved
  • intratemporal SEGMENT
    • fracture, cholesteatoma, paraganglioma, hemangioma, facial nerve schwannoma, metastasis, Bell palsy, otitis media
      • • loss of lacrimation, hyperacusis, loss of taste
  • EXTRACRANIAL PAROTID SEGMENT
    • forceps delivery, penetrating facial trauma, parotid surgery, parotid malignancy, malignant otitis externa
      • preservation of lacrimation, stapedius reflex, taste
Ear
Hearing deficit
  • CONDUCTIVE HEARING LOSS
    • decrease in air conduction via EAC, tympanic membrane, ossicular chain, oval window (sound via headphones)
      • normal bone conduction (sound via bone oscillator)
    • trauma: incudostapedial / malleoincudal subluxation; incus dislocation; stapes dislocation; stapes / malleus fracture
    • destruction of ossicular chain: otitis media
    • restriction of ossicular chain: fenestral otosclerosis
    • CT is the modality of choice!
  • SENSORINEURAL HEARING LOSS (most common)
    • elevated conduction thresholds for bone + air
  • sensory / cochlear SNHL = damage to cochlea / organ of Corti (less common)
    • bony labyrinth
      • demineralization: otosclerosis (otospongiosis), osteogenesis imperfecta, Paget disease, syphilis
      • congenital deformity: cochlear dys- / aplasia, Michel anomaly, Mondini dysplasia, enlarged vestibular aqueduct syndrome, X-linked sensorineural hearing loss
      • traumatic lesion: transverse fracture, perilymphatic fistula, cochlear concussion
      • destructive lesion: inflammatory lesion, neoplastic lesion
    • CT is the modality of choice!
  • membranous labyrinth
    • enhancement: labyrinthitis, Cogan syndrome (early phase of autoimmune interstitial keratitis), intralabyrinthine schwannoma, site of postinflammatory perilymphatic fistula
    • obliteration: labyrinthitis ossificans, Cogan syndrome (late phase)
    • hemorrhage: trauma, labyrinthitis, coagulopathy, tumor fistulization
    • Ménière disease (vertigo + fluctuating sensory sensorineural hearing loss)
    • MRI is the modality of choice!
  • neural / retrocochlear SNHL (more common)
    • = abnormalities of neurons of spiral ganglion + central auditory pathways
    • –IAC / cerebellopontine angle
      • neoplastic lesions: vestibular / trigeminal schwannoma (acoustic neuroma in 1%), meningioma, arachnoid cyst, epidermoid cyst, leptomeningeal carcinomatosis, lymphoma, lipoma, hemangioma
      • nonneoplastic lesion: sarcoidosis, meningitis, vascular loop, siderosis
    • –intraaxial auditory pathway
      (brainstem, thalamus, temporal lobe)
      • ischemic lesion
      • neoplastic lesion
      • traumatic lesion
      • demyelinating lesion
    • MRI is the modality of choice!
Pulsatile tinnitus ± Vascular Tympanic Membrane
  • = perception of a rhythmic cardiac synchronous sound of ringing / buzzing / roaring
  • No abnormality (20%)
  • Congenital vascular variants (21%)
    • Aberrant ICA
      • = result of anastomosis of enlarged inferior tympanic artery with enlarged caroticotympanic artery when cervical ICA is underdeveloped
    • Dehiscent jugular bulb
    • High-riding nondehiscent jugular bulb (= jugular megabulb)
      • high jugular bulb with diverticulum projecting cephalad into petrous temporal bone
  • Acquired vascular lesions (25%)
    • Dural AVM
    • Extracranial arteriovenous fistula
    • High-grade stenotic vascular lesion: carotid artery atherosclerosis, fibromuscular dysplasia, carotid artery dissection
    • Aneurysm involving horizontal segment of petrous ICA
  • Temporal bone tumors (31%)
    • Paraganglioma (27%): glomus tympanicum, glomus jugulare
    • Meningioma
    • Hemangioma
  • P.356

  • Miscellaneous
    • Cholesterol granuloma
Demineralization of Temporal Bone
  • Otosclerosis = otospongiosis
  • Paget disease = osteoporosis circumscripta
    • sensorineural / mixed hearing loss (cochlear involvement / stapes fixation in oval window)
    • usually lytic changes beginning in petrous pyramid + progressing laterally; otic capsule last to be affected
    • calvarial changes ± basilar impression
  • Fibrous dysplasia
    • monostotic with temporal bone involvement
    • painless mastoid swelling
    • conductive hearing loss (from narrowing of EAC / middle ear)
    • homogeneously dense thickened bone (fibro-osseous tissue less dense than calvarial bone)
    • expanded bone with preserved cortex
    • lytic lesions (less frequent)
    • sparing of membranous labyrinth, facial nerve canal, IAC is the rule
  • Osteogenesis imperfecta
    • changes similar to otosclerosis
    • van der Hoeve-de Kleyn syndrome
      • = osteogenesis imperfecta + hearing loss + blue sclerae in patients in late 2nd / early 3rd decade
  • Otosyphilis: labyrinthitis + gummatous lesion of internal auditory canal + inflammatory resorptive osteitis
    • moth-eaten permeative osteolysis of temporal bone
  • Metastasis
External Ear Masses
  • CONGENITAL
    • Atresia
  • INFLAMMATORY
    • Malignant external otitis
    • Keratosis obturans
      • bilateral process in association with chronic sinusitis + bronchiectasis
      • Age: <40 years
    • Cholesteatoma
  • BENIGN TUMOR
    • Exostosis = surfer’s ear
      • Cause: irritation by cold water
      • bony mass projecting into EAC; often multiple + bilateral
    • Osteoma
      • may invade adjacent bone
      • single in EAC / mastoid
    • Ceruminoma
      • from apocrine + sebaceous glands; bone erosion mimics malignancy
  • MALIGNANT TUMOR
    • Squamous cell carcinoma
      • • often long history of chronic suppurative otitis media = “malignant otitis”
    • Basal cell carcinoma
    • Melanoma, adenocarcinoma, adenoid cystic carcinoma
    • Metastases
      • hematogenous: breast, prostate, lung, kidney, thyroid
      • direct spread: skin, parotid, nasopharynx, brain, meninges
      • systemic: leukemia, lymphoma, myeloma
    • Histiocytosis X: in 15% of patients
Middle Ear Masses
  • CONGENITAL
    • Aberrant internal carotid artery
      • • vascular tympanic membrane
      • • pulsatile tinnitus
      • tubular soft-tissue density entering middle ear cavity posterolateral to cochlea, crossing mesotympanum along cochlear promontory, exiting anteromedial to become horizontal portion of carotid canal
      • protrusion into middle ear without bony margin
    • Dehiscent jugular bulb
  • INFLAMMATORY
    • Cholesteatoma
    • Cholesterol granuloma
    • Granulation tissue
      • linear strands partially opacifying middle ear cavity without bony erosion
  • BENIGN TUMOR
    • Adenomatous tumor (mixed pattern type)
      • intense enhancement
      • no osseous destruction
    • Glomus tumor (multiple in 10%; 8% malignant)
      • Glomus tympanicum: at cochlear promontory
        • seldom erodes bone
      • Glomus jugulare: at jugular foramen
        • invasion of middle ear from below
        • destruction of bony roof of jugular fossa + bony spur separating vein from carotid artery
    • Facial nerve schwannoma
      • • persistent Bell palsy (in 5% caused by neurinoma)
      • Location: intracanalicular > IAC
      • tubular mass in enlarged / scalloped facial canal
    • Ossifying hemangioma
    • Choristoma = ectopic mature salivary tissue
    • Endolymphatic sac tumor
      • arises from region of vestibular aqueduct
    • Meningioma
  • MALIGNANT TUMOR
    • Squamous cell carcinoma
    • Metastasis
    • Rhabdomyosarcoma
      • Location: orbit > nasopharynx > ear
    • Adenocarcinoma (rare), adenoid cystic carcinoma
Mass on Promontory
  • [promontory = bone over basal turn of cochlea]
  • Glomus tympanicum
  • Congenital cholesteatoma
  • Aberrant carotid artery
  • Persistent stapedial artery
P.357

Inner Ear Masses
  • CONGENITAL
    • Congenital / primary cholesteatoma = epidermoid tumor (3rd most common CPA tumor)
  • INFLAMMATION
    • Cholesterol granuloma
    • Petrous apex mucocele
  • TUMOR
    • Glomus jugulare tumor
    • Hemangioma, fibro-osseous lesion
    • Metastasis
    • Facial nerve neurinoma
    • Large CPA tumors: acoustic neuroma, meningioma (2nd most common CPA tumor)
Sinuses
Opacification of Maxillary Sinus
  • WITHOUT BONE DESTRUCTION
    • Sinus aplasia / hypoplasia
      • Age: NOT routinely visualized at birth, by age 6 antral floor at level of middle turbinate, by age 15 of adult size
      • Location: uni- / bilateral
      • depression of orbital floor with enlargement of orbit
      • lateral displacement of lateral wall of nasal fossa with large turbinate
    • Maxillary dentigerous cyst usually containing a tooth / crown; without tooth = primordial dentigerous cyst
    • Ameloblastoma
    • Acute sinusitis
      • air-fluid level
  • WITH BONE DESTRUCTION
    • Maxillary sinus tumor
    • Infection: aspergillosis, mucormycosis, TB, syphilis
    • Wegener granulomatosis; lethal midline granuloma
    • Blowout fracture
Paranasal Sinus Masses
  • Mucocele
    • Cause: obstruction of a paranasal sinus
    • ± bone remodeling / sinus expansion
  • Mucus retention cyst
    • Cause: obstruction of small seromucinous gland
    • Location: commonly in floor of maxilla
    • smoothly marginated soft-tissue mass
  • Sinonasal polyp
  • Antrochoanal polyp
  • Inverting papilloma
  • Sinusitis
  • Carcinoma
Granulomatous Lesions of Sinuses
  • Chronic irritants
    • Beryllium
    • Chromate salts
  • Infection
    • Tuberculosis
    • Actinomycosis
    • Rhinoscleroma
    • Yaws
    • Blastomycosis
    • Leprosy
    • Rhinosporidiosis
    • Syphilis
    • Leishmaniosis
    • Glanders
  • Autoimmune disease
    • Wegener granulomatosis
  • Lymphoma-like lesions
    • Midline granuloma
  • Unclassified
    • Sarcoidosis
Hyperdense Sinus Secretions
  • Inspissated secretions
  • Fungal sinusitis
  • Hemorrhage into sinus
  • Chronic sinusitis infected with bacteria (in particular in very long-standing disease / cystic fibrosis)
Opacified Sinus & Expansion / Destruction
mnemonic: PLUMP FACIES
  • Plasmacytoma
  • Lymphoma
  • Unknown etiology: Wegener granulomatosis
  • Mucocele
  • Polyp
  • Fibrous dysplasia, Fibroma (ossifying)
  • Aneurysmal bone cyst, Angiofibroma
  • Cancer
  • Inverting papilloma
  • Esthesioneuroblastoma
  • Sarcoma: ie, rhabdomyosarcoma
Nose
Nasal Vault Masses
  • BENIGN
    • Sinonasal polyp
    • Inverted papilloma
    • Hemangioma
      • history of epistaxis
    • Pyogenic granuloma
      • pedunculated lobular mass
    • Granuloma gravidarum = nasal hemangioma of pregnancy
    • Hemangiopericytoma
    • Juvenile nasopharyngeal angiofibroma
      • arises in superior nasopharynx with extension into nose via posterior choana
  • MALIGNANT
    • Lymphoma
    • Melanoma
    • Vascular metastasis
Mass in Nasopharynx
mnemonic: NASAL PIPE
  • Nasopharyngeal carcinoma
  • Angiofibroma (juvenile)
  • P.358

  • Spine / skull fracture
  • Adenoids
  • Lymphoma
  • Polyp
  • Infection
  • Plasmacytoma
  • Extension of neoplasm (sphenoid / ethmoid sinus ca.)
Congenital Midline Nasal Mass
  • = result of faulty regression of embryologic dural diverticulum through foramen cecum + fonticulus frontalis (= nasofrontal fontanel) from the prenasal space
    Frequency: 1:20,000 to 1:40,000 births
  • Dermoid cyst
  • Epidermoid cyst
  • Nasal glioma = nasal cerebral heterotopia
  • Nasal encephalocele
  • Hemangioma / lymphangioma
  • Dacryocystocele
  • Dacryocystitis
Pharynx
Parapharyngeal Space Mass
  • BENIGN
    • Asymmetric pterygoid venous plexus
      • racemose, enhancing area along medial border of lateral pterygoid muscle
    • Abscess
      Origin: pharyngitis (most common), dental infection, parotid calculus disease, penetrating trauma
    • Atypical second branchial cleft cyst
      Age: child / young adult
    • protruding parotid gland
    • bulging posterolateral pharyngeal wall
    • cystic mass projecting from deep margin of faucial tonsil toward skull base
  • Pleomorphic adenoma of ectopic salivary tissue / of deep lobe of parotid gland (common)
  • Schwannoma, neurofibroma
    • Origin: usually from cranial nerve X
    • carotid artery pushed anteriorly
  • Paraganglioma
    • posterior to carotid artery
    • extremely vascular (numerous flow voids)
    • Lipoma
  • MALIGNANT
    • Squamous cell carcinoma
      • direct extension from pharyngeal mucosal space
      • vertical extension to skull base / hyoid bone
    • Salivary gland malignancy
Pharyngeal Mucosal Space Mass
  • Asymmetric fossa of Rosenmüller = lateral pharyngeal recess = asymmetry in amount of lymphoid tissue
  • Tonsillar abscess
    • sore throat, fever, painful swallowing
  • Postinflammatory retention cyst
    • 1–2-cm well-circumscribed cystic mass
  • Postinflammatory calcification
    • remote history of severe pharyngitis
    • multiple clumps of calcification
  • Benign mixed tumor
    • pedunculated mass arising from minor salivary glands
    • oval / round well-circumscribed mass protruding into airway
  • Squamous cell carcinoma
    • infiltrating mass with epicenter medial to + invading parapharyngeal space
    • middle-ear fluid (eustachian tube malfunction)
    • cervical adenopathy
  • Non-Hodgkin lymphoma
  • Minor salivary gland malignancy
  • Thornwaldt cyst
    • Most common congenital head and neck cyst in a child!
Masticator Space Mass
  • BENIGN
    • Asymmetric accessory parotid gland
      • Incidence: 21% of general population
        Location: usually on surface of masseter muscle
      • prominent salivary gland tissue
    • Benign masseteric hypertrophy
      • Cause: bruxism (= nocturnal gnashing of teeth)
      • homogeneous enlargement of one / both masseters
    • Odontogenic abscess / mandibular cysts
      • bad dentition + trismus
    • Lymphangioma, hemangioma
  • MALIGNANT
    • Sarcoma (chondro-, osteo-, soft-tissue sarcoma, especially rhabdomyosarcoma in children)
      • infiltrating mass with mandibular destruction
    • Malignant schwannoma
      • tubular mass along cranial nerve V3
    • Non-Hodgkin lymphoma
    • Infiltrating squamous cell carcinoma
      • extending from pharyngeal mucosa
    • Salivary gland malignancy (mucoepidermoid carcinoma, adenoid cystic carcinoma)
      • extending from parotid gland
    • N.B.: (1) check course of V3 to foramen ovale for skull base extension to Meckel cave area + cavernous sinus
      • check for extension to pterygopalatine fossa to infraorbital fissure into orbit
Carotid Space Mass
  • VASCULAR LESION
    • Ectatic common / internal carotid artery
    • Carotid artery aneurysm / pseudoaneurysm
    • Asymmetric internal jugular vein
    • Jugular vein thrombosis
  • BENIGN TUMOR
    • Paraganglioma (carotid body tumor + glomus jugulare + glomus vagale)
    • P.359

    • Schwannoma
      • displacement of carotid artery anteromedially + internal jugular vein posteriorly
      • well-encapsulated mass
    • Neurofibroma of cranial nerves IX, X, XI
    • Branchial cleft cyst
  • MALIGNANT TUMOR
    • Nodal metastasis from squamous cell carcinoma to interior jugular chain (common)
      • encasement of carotid artery = inoperable
    • Non-Hodgkin lymphoma
Retropharyngeal Space Mass
  • INFECTION
    • Reactive lymphadenopathy
      • nodes >10 mm in diameter
    • Abscess:
      • bow-tie shape
    • BENIGN TUMOR
      • Hemangioma
      • Lipoma
    • MALIGNANT TUMOR
      • Metastasis to retropharyngeal nodes
        • from nasopharyngeal squamous cell carcinoma, melanoma, thyroid carcinoma
        • N.B.: sentinel node of Rouviere (= lateral retropharyngeal node) is an early sign of nasopharyngeal cancer before primary mass becomes obvious
      • Non-Hodgkin lymphoma
      • Direct invasion by squamous cell carcinoma
Prevertebral Space Mass
  • PSEUDOTUMOR
    • Anterior disk herniation
    • Vertebral body osteophyte
  • INFLAMMATION
    • Vertebral body osteomyelitis
    • Abscess
      • extension from retropharyngeal space / osteomyelitis / diskitis / epidural abscess
    • TUMOR
      • Chordoma
      • Vertebral body metastasis: lung, breast, prostate, non-Hodgkin lymphoma, myeloma
        • Metastases to prevertebral space = inoperable
Larynx
Vocal Cord Paralysis
  • Birth injury
  • Arnold-Chiari malformation
  • Intracranial tumor
  • Mediastinal mass / cyst
  • Vascular ring
  • Thyroidectomy
  • Malignancy
  • fixed vocal cords (fluoroscopy)
Epiglottic Enlargement
  • NORMAL VARIANT
    • Prominent normal epiglottis
    • Omega epiglottis
  • INFLAMMATION
    • Acute / chronic epiglottitis
    • Angioneurotic edema
    • Stevens-Johnson syndrome
    • Caustic ingestion
    • Radiation therapy
  • MASSES
    • Epiglottic cyst
    • Aryepiglottic cyst
    • Foreign body
Aryepiglottic Cyst
  • Retention cyst
  • Lymphangioma
  • Cystic hygroma
  • Thyroglossal cyst
  • may be symptomatic at birth
  • well-defined mass in aryepiglottic fold
Laryngeal Neoplasms
  • SQUAMOUS CELL CARCINOMA (95–98%)
    • endoscopically visible due to mucosal involvement
  • NON-SQUAMOUS CELL NEOPLASMS (2–5%)
    • malignant:benign = 1:1
    • vasoformative tumor____________33%
      • Benign
        • Hemangioma
        • Lymphangioma
        • Angiofibroma
        • Angiomatosis
        • Granuloma pyogenicum
        • Arteriovenous fistula
        • Phlebectasia, telangiectasia
      • Malignant
        • Angiosarcoma (Kaposi sarcoma)
          • Location: epiglottis (most frequent)
          • intensely enhancing mass
        • Hemangiopericytoma
      • chondrogenic tumor___________________20%
        • Chondroma
        • Chondrosarcoma
        • Osteosarcoma
      • hematopoietic tumor__________________12%
        • Hodgkin / non-Hodgkin lymphoma / leukemia
        • Plasmacytoma
        • Pseudolymphoma
      • salivary gland tumor__________________10%
        • Pleomorphic adenoma
        • Adenoid cystic carcinoma
        • Mucoepidermoid carcinoma
        • Adenocarcinoma
      • fatty-tissue tumor__________________7%
        • Lipoma
        • Liposarcoma
      • P.360

      • metastasis__________________7%
        • skin (melanoma) > kidney > breast > lung > prostate > colon > stomach > ovary
      • neurogenic tumor__________________5%
      • myogenic tumor__________________2%
      • fibrohistiocytic tumor__________________2%
Airways
Inspiratory Stridor in Children
  • Croup
  • Congenital subglottic stenosis
  • Subglottic hemangioma
  • Airway foreign body
  • Esophageal foreign body
  • Epiglottitis
Airway Obstruction in Children
Nasopharyngeal Narrowing
  • (a) Congenital: Choanal atresia, choanal stenosis, encephalocele
    (b) Inflammatory: Adenoidal enlargement, polyps
    (c) Neoplastic: Juvenile angiofibroma, rhabdomyosarcoma, teratoma, neuroblastoma, lymphoepithelioma
    (d) Traumatic: Foreign body, hematoma, rhinolith
Oropharyngeal Narrowing
  • (a) Congenital: Glossoptosis + micrognathia (Pierre Robin, Goldenhar, Treacher Collins syndrome), macroglossia (cretinism, Beckwith-Wiedemann syndrome)
    (b) Inflammatory: Abscess, tonsillar hypertrophy
    (c) Neoplastic: Lingular tumor / cyst
    (d) Traumatic: Hematoma, foreign body
Retropharyngeal Narrowing
  • = potential space (normally <3/4 of AP diameter of adjacent cervical spine in infants / <3 mm in older children)
    (a) Congenital: Branchial cleft cyst, ectopic thyroid
    (b) Inflammatory: Retropharyngeal abscess
    (c) Neoplastic: Cystic hygroma (originating in posterior cervical triangle with extension toward midline + into mediastinum), neuroblastoma, neurofibromatosis, hemangioma
    (d) Traumatic: Hematoma, foreign body
    (e) Metabolic: Hypothyroidism
Vallecular Narrowing
  • = valleys on each side of glossoepiglottic folds between base of tongue + epiglottis
    (a) Congenital: Congenital cyst, ectopic thyroid, thyroglossal cyst
    (b) Inflammatory: Abscess
    (c) Neoplastic: Teratoma
    (d) Traumatic: Foreign body, hematoma
Supraglottic Narrowing
  • = area between epiglottis and true vocal cords
    (a) Congenital: Aryepiglottic fold cyst
    (b) Inflammatory: Acute bacterial epiglottitis, angioneurotic edema
    (c) Neoplastic: Retention cyst, cystic hygroma, neurofibroma
    (d) Traumatic: Foreign body, hematoma, radiation, caustic ingestion
    (e) Idiopathic: Laryngomalacia
Glottic Narrowing
  • = area of true vocal cords
    (a) Congenital: Laryngeal atresia, laryngeal stenosis, laryngeal web (anterior commissure)
    (b) Neoplastic: Laryngeal papillomatosis
    (c) Neurogenic: Vocal cord paralysis (most common)
    (d) Traumatic: Foreign body, hematoma
Subglottic Narrowing
= short segment between undersurface of true vocal cords + inferior margin of cricoid cartilage is the narrowest portion of child’s airway
(a) Congenital: Congenital subglottic stenosis
(b) Inflammatory: Croup
(c) Neoplastic: Hemangioma, papillomatosis
(d) Traumatic: Acquired stenosis (result of prolonged endotracheal intubation in 5%), granuloma
(e) Idiopathic: Mucocele = mucous retention cyst (rare complication of prolonged endotracheal intubation)
Neck
Solid Neck Mass
Solid Neck Mass In Neonate
  • Cystic hygroma
  • Hemangioma
  • Neuroblastoma
  • Teratoma
  • Fibromatosis colli
Solid Neck Mass in Childhood
  • Lymphadenopathy
  • Fibromatosis colli
  • Aggressive fibromatosis
  • Malignancy: neuroblastoma (most common), lymphoma, embryonal rhabdomyosarcoma
  • Teratoma
  • Hemangioma
  • Cervicothoracic lipoblastomatosis
  • Lipoma
  • Thyroid mass / lingual thyroid
  • Parathyroid adenoma
  • Ectopic thymus
Lymph node enlargement of neck
  • NORMAL LYMPH NODES
    • few small oval hypoechoic
    • ± central linear echogenicity (= invaginating hilar fat)
    • larger in transverse than anteroposterior dimension
  • P.361

  • CERVICAL ADENITIS
    • Location:  posterior cervical triangle
    • Tuberculous adenitis
      • multichambered centrally hypoattenuating mass
      • thick enhancing rim
      • peripheral calcifications
    • MALIGNANT LYMPH NODES
      • increased anteroposterior diameter
      • prominent calcifications suggestive of medullary thyroid cancer
      • axial diameter of >15 in jugulodigastric region / >11 mm elsewhere (in squamous cell carcinoma)
      • CT:
        • marginal enhancement
        • central necrosis (regardless of size)
        • fuzzy borders as sign of extracapsular extension
Low-density Nodes with Peripheral Enhancement
  • Tuberculosis
  • Metastatic malignancy
  • Lymphoma
  • Inflammatory conditions
Lymph Node Metastasis by Location
  • @ supraclavicular
    • head & neck, lung, breast, esophagus
  • @ INTERNAL JUGULAR
    • supraglottic larynx, esophagus, thyroid
  • @ midjugular
    • tongue, pharynx, supraglottic larynx
  • @ JUGULODIGASTRIC
    • nasopharynx, oropharynx, tonsils, parotid gland, supraglottic larynx
  • @ SUBMANDIBULAR
    • skin, submandibular gland, base of tongue
  • @ POSTERIOR TRIANGLE
    • nasopharynx, base of tongue
  • @ LATERAL PHARYNGEAL
    • nasopharynx, oropharynx
Congenital Cystic Lesions of Neck
  • Thyroglossal duct cyst
    • Location:  anterior cervical triangle close to midline between foramen cecum + thyroid isthmus
  • Lymphangioma / cystic hygroma
    • Location:  mostly in posterior cervical triangle, occasionally in floor of mouth / tongue
  • Branchial cleft anomalies
    • often noted during upper respiratory infection
    • 2nd branchial cleft cyst
      • Location:  near angle of mandible anterior to sternocleidomastoid muscle
    • branchial cleft fistula
      • Location:  apex of piriform sinus to thyroid
    • Cervical dermoid / epidermoid cyst
      • Location:  floor of mouth
    • Cervical thymic cyst
    • Parathyroid cyst
      • Age:  30–50 years
      • hormonally inactive
      • noncolloidal cyst near lower pole of thyroid gland
    • Cervical bronchogenic cyst
      Cause: anomalous foregut development
      Histo: columnar ciliated pseudostratified epithelial lining
    • M:F = 3:1
    • draining sinus in suprasternal notch / supraclavicular area
    • cyst up to 6 cm in diameter
    • indentation of trachea
  • Laryngocele
Air-containing Masses of Neck
  • Laryngocele
  • Tracheal diverticulum arising from anterior wall of trachea close to thyroid
  • Zenker diverticulum
  • Lateral pharyngeal diverticulum located in tonsillar fossa / vallecula / pyriform fossa
Fat-containing Masses of Neck
  • Dermoid cyst
  • Lipoblastoma
  • Liposarcoma (extremely rare <10 years of age)
Salivary glands
Parotid Gland Enlargement
  • LOCALIZED INFLAMMATION / INFECTION
    • Chronic recurrent sialadenitis
    • Sialosis
    • Sarcoidosis
    • Tuberculosis
    • Cat-scratch fever
    • Syphilis
    • Parotid abscess secondary to acute bacterial (suppurative) sialadenitis
    • Reactive adenopathy
    • Parotitis: mumps (most common parotid disease in children), HIV
  • SYSTEMIC AUTOIMMUNE RELATED DISEASE
    • Sjögren disease (= myoepithelial sialadenitis)
    • Mikulicz disease
  • NEOPLASM
    • Frequency: 90–95% occur in parotid gland, 5% in submandibular + sublingual glands; only 1% of all pediatric tumors!
    • benign tumor
      • Pleomorphic / monomorphic adenoma
      • Cystadenolymphoma (= Warthin tumor)
      • Benign lymphoepithelial cysts (AIDS)
      • Lipoma
      • Facial nerve neurofibroma
      • Oncocytoma
      • Parotid hemangioma
      • Angiolipoma
    • primary malignant tumor
      • Mucoepidermoid carcinoma
      • Adenoid cystic carcinoma (= cylindroma)
      • Malignant mixed tumor
      • Adenocarcinoma
      • P.362

      • Acinus cell carcinoma
      • Rhabdomyosarcoma
    • metastatic tumor
      • Parotid gland undergoes late encapsulation, which leads to incorporation of lymph nodes!
      • Squamous cell carcinoma
      • Melanoma of periauricular region
      • Non-Hodgkin lymphoma
      • Thyroid carcinoma
  • LYMPHOPROLIFERATIVE DISORDER
    • Lymphoma / leukemia
    • Primary non-Hodgkin lymphoma (MALToma)
  • CONGENITAL
    • First branchial cleft cyst
Multiple Lesions of Parotid Gland
  • Warthin tumor
  • Metastases to lymph nodes: squamous cell carcinoma of skin, malignant melanoma, non-Hodgkin lymphoma
  • Benign lymphoepithelial cysts (AIDS)
Thyroid
Congenital Dyshormonogenesis
  • Trapping defect
    • = defective cellular uptake of iodine into thyroid, salivary glands, gastric mucosa;
    • High doses of inorganic iodine facilitate diffusion into thyroid permitting a normal rate of thyroid hormone synthesis
    • Normal ratio of iodine concentrations for gastric juice:plasma = 20:1
    • nearly entire dose of administered radioiodine is excreted within 24 hours
  • Organification defect
    • = deficient peroxidase activity, which catalyzes the oxidation of iodide by H2O2 to form monoiodotyrosine (MIT) / diiodotyrosine (DIT)
    • high serum TSH
    • low serum T4
    • diffuse symmetric thyromegaly
    • high thyroidal uptake of radioiodine / pertechnetate
    • rapid I-131 turnover
    • positive perchlorate washout test
    • Pendred syndrome = autosomal recessive trait of deficient peroxidase regeneration characterized by hypothyroidism + goiter + nerve deafness
  • Deiodinase (dehalogenase) defect
    • = deficient deiodination of MIT / DIT to release iodide, which is reutilized to synthesize thyroid hormone production
    • hypothyroidism
    • identification of MIT + DIT in serum + urine following administration of I-131
    • “intrinsic” iodine deficiency goiter
    • high thyroidal I-131 uptake
    • rapid intrathyroidal turnover of I-131
  • Thyroxin-binding globulin (TBG) deficiency
    • abnormal T4 transport
    • low bound serum T4 concentration
    • euthyroid
  • End-organ resistance to thyroid hormone
    • high serum T4
    • euthyroid / hypothyroid
    • growth retardation
    • goiter
    • stippled epiphyses
Thyrotoxicosis
  • = clinical syndrome of increased systemic metabolism
  • Cause:
    • increased thyroid function
      • Graves disease
        • gland may be normal in size in early stage
      • Marine-Lenhart syndrome = nodular Graves = Graves disease coexistent with multinodular goiter
      • Toxic autonomous nodule
      • Toxic multinodular goiter
    • thyroid inflammation
      • Subacute thyroiditis
      • Silent thyroiditis
      • Postpartum thyroiditis
    • iodine-induced hyperthyroidism
    • hyperthyroidism of extrathyroidal origin
      • Factitious hyperthyroidism
      • Ectopic thyroid hormone production:metastatic thyroid cancer, toxic struma ovarii
      • Thyrotropin-induced hyperthyroidism (pituitary adenoma)
  • • elevated free T4, elevated free T3, or both
Hyperthyroidism
  • = overactivity of thyroid due to excess thyroid hormone
  • tachycardia, weight loss, muscle weakness, anxiety, decreased temperature tolerance
    • Graves disease = toxic diffuse goiter (most common)
    • Toxic multinodular goiter
    • Solitary toxic adenoma
    • Iodine-induced hyperthyroidism = Jod-Basedow
    • Thyroiditis
      • Hashimoto thyroiditis = chronic lymphocytic thyroiditis
      • Subacute thyroiditis = de Quervain thyroiditis
      • Painless thyroiditis
      • US:
        • decrease in overall echogenicity
        • discrete nodules (50%)
      • Thyrotoxicosis medicamentosa / factitia surreptitious self-administration of thyroid hormones
      • Struma ovarii = ovarian teratoma containing thyroid tissue
      • Hydatidiform mole / choriocarcinoma / testicular trophoblastic carcinoma = stimulation of thyroid by hCG
      • Pituitary hyperthyroidism = pituitary neoplasm
        • ± acromegaly
        • ± hyperprolactinemia
      • Thyroid carcinoma / hyperfunctioning metastases very rare (25 cases)
P.363

Radioiodine Therapy for Hyperthyroidism
  • Dose:
    (a) empiric: 15–30 mCi
    (b) calculation (Y): 80–160 μCi/gram
  • Calculation:
    Dose [mCi] = (gland weight [gram] × Y [μCi/gram]) divided by 24-hour uptake
Hypothyroidism
  • PRIMARY HYPOTHYROIDISM (most common)
    • = thyroid’s inability to produce sufficient thyroid hormone
    • Agenesis of thyroid
    • Congenital dyshormonogenesis
    • Chronic thyroiditis
    • Previous radioiodine therapy
    • Ectopic thyroid (1:4,000)
  • SECONDARY HYPOTHYROIDISM
    • = failure of anterior pituitary to release sufficient quantities of TSH
    • Sheehan syndrome
    • Head trauma
    • Pituitary tumor (primary / secondary)
    • Aneurysm
    • Surgery
  • TERTIARY / HYPOTHALAMIC HYPOTHYROIDISM
    • = failure of hypothalamus to produce sufficient amounts of TRH
Decreased / No Uptake of Radiotracer
  • BLOCKED TRAPPING FUNCTION
    • Iodine load (most common)
      • = dilution of tracer within flooded iodine pool (from administration of radiographic contrast / iodine-containing medication)
      • Suppression usually lasts for 4 weeks!
    • Exogenous thyroid hormone (replacement therapy) suppresses TSH release
  • BLOCKED ORGANIFICATION
    • Antithyroid medication (propylthiouracil (PTU) / methimazole) / goitrogenic substances
    • Tc-99m uptake not inhibited
  • DIFFUSE PARENCHYMAL DESTRUCTION
    • Subacute / chronic thyroiditis
  • HYPOTHYROIDISM
    • Congenital hypothyroidism
    • Surgical / radioiodine ablation
    • Thyroid ectopia (struma ovarii, intrathoracic goiter) mnemonic: H MITTE
    • Hypothyroidism (congenital)
    • Medications: PTU, perchlorate, Cytomel, Synthroid, Lugol solution
    • Iodine overload (eg, after IVP)
    • Thyroid ablation (surgery, radioiodine)
    • Thyroiditis (subacute / chronic)
    • Ectopic thyroid hormone production
Increased Uptake of Radiotracer
mnemonic: THRILLEr
  • Thyroiditis (early Hashimoto)
  • Hyperthyroidism (diffuse / nodular)
  • Rebound after withdrawal of antithyroid medication
  • Iodine starvation
  • Low serum albumin
  • Lithium therapy
  • Enzyme defect
Prominent Pyramidal Lobe
  • = distal remnant of thyroid descent tract
  • Normal variant: present in 10%
  • Hyperthyroidism
  • Thyroiditis
  • S/P thyroid surgery
  • DDx:  esophageal activity from salivary excretion (disappears after glass of water)
Thyroid Calcifications
  • = benign calcifications = stromal calcifications in adenoma
  • coarse calcifications with rough outline
  • alignment along periphery of lesion
  • irregular distribution
Psammoma Bodies
  • = microcalcifications (<1 mm) occur in 54% of thyroid neoplasms
  • seen on xeroradiography in 94%
  • Papillary carcinoma 61%
  • Follicular carcinoma 26%
  • Undifferentiated carcinoma 13%
Cystic Areas in Thyroid
  • 15–25% of all thyroid nodules!
  • Anechoic fluid + smooth regular wall:
    • Colloid accumulation in goiter = colloid-filled dilated macrofollicle
    • Simple cyst (extremely uncommon)
  • Solid particles + irregular outline:
    • Hemorrhagic colloid nodule
    • Hemorrhagic adenoma (30%)
    • Necrotic papillary cancer (15%)
    • Liquefaction necrosis in adenoma / goiter
    • Abscess
    • Cystic parathyroid tumor
  • bloody fluid = benign / malignant lesion
  • clear amber fluid = benign lesion
  • Cystic lesions often yield insufficient numbers of cells!
Thyroid Nodule
  • Incidence:  (increasing with age)
    • 4–8% by palpation (>2 cm in 2%, 1–2 cm in 5%, <1 cm in 1%); M:F = 1:4
    • 10–41% by thyroid US if clinically normal: multiple in 38%, solitary in 12% (occult small cancers found in 4%)
    • 50% by autopsy
  • THYROID ADENOMA
    • Adenomatous nodule (42–77%)
    • Follicular adenoma (15–40%)
    • Ectopic parathyroid adenoma
  • P.364

  • INFLAMMATION / HEMORRHAGE
    • Inflammatory lymph node in subacute + chronic thyroiditis
    • Hemorrhage / hematoma: frequently associated with adenomas
    • Abscess
  • CARCINOMA (8–17%)
    • Higher risk of malignancy if
      • patient <20 and >60 years of age
      • Hx of radiation therapy to neck / upper chest
      • family Hx of thyroid cancer / MEN syndrome
      • new nodule in long-standing goiter
      • nodule firm
      • growth rapid
      • nodule fixed to adjacent structures
      • vocal cord paralyzed
      • regional lymph nodes enlarged
    • Thyroid carcinoma
      • papillary carcinoma (70%)
      • follicular (15%)
      • medullary carcinoma (5–10%)
      • anaplastic carcinoma (5%)
      • thyroid lymphoma (5%)
    • Nonthyroidal neoplasm metastasis from breast, lung, kidney, malignant melanoma, Hodgkin disease
    • Hürthle cell carcinoma
      • very thin hypoechoic halo
    • Carcinoma in situ
      • echogenic area inside a goiter nodule
Role of fine-needle aspiration biopsy (FNAB)
  • FNAB as initial test leads to a better selection of patients for surgery than any other test!; (large-needle biopsy has more complications with no increase in diagnostic yield)
US Feature Recommendation
Solitary nodule  
  Microcalcifications Strongly consider US-guided FNA if ≥1 cm
  Solid / coarse calcifications Strongly consider US-guided FNA if ≥1.5 cm
  Mixed solid / cystic or almost entirely cystic with mural nodule Consider US-guided FNA if ≥2 cm
Substantial growth since prior US examination Consider US-guided FNA
Almost entirely cystic Biopsy probably unnecessary
Multiple nodules Biopsy of individual nodules prioritized as recommended above
  • Diagnostic accuracy (70–97%):
    • 70–80% negative
    • 10% positive specimens (3–6% false-positive rate often due to Hashimoto thyroiditis)
    • 10–20% indeterminate
    • Up to 20% nondiagnostic material (too few cells)
Role of imaging
  • Imaging cannot reliably distinguish malignant + benign nodules!
  • Radionuclide scanning:
    • Useful in indeterminate cytology
    • Hyperfunctioning nodule is almost always benign!
  • US:
    • Best method to determine volume of nodule
    • Useful during follow-up to distinguish nodular growth from intranodular hemorrhage
Discordant Thyroid Nodule
  • = nodule “warm” on Tc-99m pertechnetate scan + “cold” on I-123 scan, which indicates Tc-99m trapping but no organification
  • Cause:
    • Malignancy: follicular / papillary carcinoma
    • <5% of thyroid carcinomas manifest as discordant nodules
  • Benign lesion: follicular adenoma / adenomatous hyperplasia
    • (autonomous nontoxic nodules have accelerated iodine turnover and discharge radioiodine as hormone within 24 hours)
Rx: thyroid fine-needle aspiration biopsy
Hot Thyroid Nodule
Incidence:  8% of Tc-99m pertechnetate scans
  • Adenoma
    • Autonomous adenoma = TSH-independent
      • euthyroid (80%), thyrotoxicosis (20%)
      • partial / total suppression of remainder of gland
    • Adenomatous hyperplasia = TSH-dependent secondary to defective thyroid hormone production
  • Thyroid carcinoma (extremely rare)
    • discordant uptake
  • N.B.: any hot nodule on Tc-99m scan must be imaged with I-123 to differentiate between autonomous or cancerous lesion
Cold Thyroid Nodule
  • BENIGN TUMOR
    • Nonfunctioning adenoma
    • Cyst (11–20%)
    • Involutional nodule
    • Parathyroid tumor
  • INFLAMMATORY MASS
    • Focal thyroiditis
    • Granuloma
    • Abscess
  • MALIGNANT TUMOR
    • Carcinoma
    • Lymphoma
    • Metastasis
P.365

  • US features of cold nodule:
    • hypoechoic (71%)
    • isoechoic (22%)
    • mixed echogenicity (4%)
    • hyperechoic (3%)
    • cystic (rarely malignant)
  • A palpable cold nodule in a patient with Graves disease has a high likelihood of malignancy (4%)!
  • mnemonic: CATCH LAMP
    • Colloid cyst
    • Adenoma (most common)
    • Thyroiditis
    • Carcinoma
    • Hematoma
    • Lymphoma, Lymph node
    • Abscess
    • Metastasis (kidney, breast)
    • Parathyroid
  • Probability of a cold nodule to represent thyroid cancer:
    • Solitary cold nodules by scintigraphy are multinodular by US in 20–25%!
    • 15–25% for solitary cold nodule
    • 1–6% for multiple nodules (DDx: multinodular goiter)
    • with history of neck irradiation in childhood
      • solitary nodule found in 70% (cancerous in 31%)
      • multiple nodules found in 25% (cancerous in 37%)
      • normal thyroid scan found in 5% (cancer detected in 20%)
P.366

Anatomy and Function of Neck Organs
Frontal Laryngogram during Phonation
Lateral Laryngogram
Paranasal sinuses
  • Mucus production of 1 L/day; mucus blanket turns over every 20–30 minutes; irritants are propelled toward nasopharynx at a rate of 1 cm/minute
Maxillary Sinus
Size: 6–8 cm at birth
Walls: roof = floor of orbit; posterior wall abuts pterygopalatine fossa
Extension: 4–5 mm below level of nasal cavity by age 12
Ostium: maxillary ostium + infundibulum enter middle meatus within posterior aspect of hiatus semilunaris; additional ostia may be present
Plain film: present at birth; visible at 4–5 months; completely developed by 15 years of age
Variations: sinus hypoplasia in 9%; aplasia in 0.4%
Ethmoid Sinuses
Size: adult size by age 12; 3–18 air cells per side
Walls: roof = floor of anterior cranial fossa; lateral wall = lamina papyracea
Plain film: very small at birth; visible at 1 year of age; completely developed by puberty
  • anteromedial ethmoid air cells
    • 2–8 cells with a total area of 24 × 23 × 11 mm
      Ostia: opening into anterior aspect of hiatus semilunaris of middle meatus (anterior group), opening into ethmoid bulla (middle group)
    • AGGER NASI CELLS
      • = anteriormost ethmoid air cells in front of the attachment of middle turbinate to cribriform plate near the lacrimal duct
      • = anterior, lateral + inferior to frontoethmoidal recess = anteromedial margin of orbit
        Prevalence: present in >90%
    • ETHMOIDAL BULLA
      • = ethmoidal air cell above + posterior to infundibulum + hiatus semilunaris, located outside the lamina papyracea at the lateral wall of the middle meatus
    • HALLER CELLS
      • = anterior ethmoid air cells inferolateral to ethmoidal bulla, on lateral wall of infundibulum, along inferior margin of orbit / roof of maxillary sinus, protruding into maxillary sinus
        Prevalence: 10–45%
  • posterior ethmoid air cells
    • 1–8 cells, larger cells, total area smaller than that of anteromedial group
      Location: behind the basal (= ground) lamella of the middle turbinate
      Ostium: into superior meatus / supreme meatus, ultimately draining into sphenoethmoidal recess of nasal cavity
    • ONODI CELL
      • = most posterior ethmoid air cell pneumatized into sphenoid bone ± surrounding the optic canal
        Location: superolateral to sphenoid sinus
Frontal Sinus
Size: 28 × 24 × 20 mm in adults, rapid growth until the late teens
Walls: posterior wall = anterior cranial fossa; inferior wall = anterior portion of roof of orbit
Ostium: into frontal recess of middle meatus via frontoethmoidal recess (= nasofrontal duct)
Plain film: visible at age 6 years
Variations: sinus aplasia in up to 4% (in 90% with Down syndrome)
Sphenoid Sinus
Size: 20 × 23 × 17 mm in adults, small evagination of sphenoethmoidal recess at birth, invasion of sphenoid bone begins at age 5 years; aerated extensions into pterygoid plates (44%) + into clinoid processes (13%)
Walls: roof = floor of sella turcica; anterior wall shared with ethmoid sinuses; posterior wall = clivus; inferior wall = roof of nasopharynx
Ostium: 10 mm above sinus floor into sphenoethmoidal recess posterior to superior meatus at level of sphenopalatine foramen
Plain film: appears by 3 years of age; continues to grow posteriorly + inferiorly into the sella until adulthood
P.367

Ostiomeatal unit
  • = area of superomedial maxillary sinus + middle meatus as the common mucociliary drainage pathway of frontal maxillary, and anterior + middle ethmoid air cells into the nose
    Coronal CT: visualized on two or three 3-mm-thick sections
  • Components:
    • Infundibulum
      • = flattened conelike passage between inferomedial border of orbit / ethmoid bulla (laterally) + uncinate process (medially) + maxillary sinus (inferiorly) + hiatus semilunaris (superiorly)
    • Uncinate process
      • = key bony structure in lateral nasal wall below hiatus semilunaris in middle meatus defines hiatus semilunaris together with adjacent ethmoid bulla
      • pneumatized in <2.5% of patients
    • Ethmoid bulla
      • located in cephalad recess of middle meatus
    • Hiatus semilunaris
      • = final segment for drainage of maxillary sinus; located just inferior to ethmoid bulla in middle meatus
    • Ostia:
      • multiple ostia from anterior ethmoid air cells (at its anterior aspect)
      • maxillary ostium infundibulum (at its posterior aspect)
  • Anatomic variations predisposing to ostiomeatal narrowing:
    • Concha bullosa (4–15%) = aerated / pneumatized middle turbinate
    • Intralamellar cell = air cell within vertical portion of middle turbinate
    • Oversized ethmoid bulla
    • Haller cells
      View of Lateral Nasal Wall (turbinates removed)
      Coronal Scan of Ostiomeatal Unit
    • Uncinate process bulla
    • Bowed nasal septum
    • Paradoxical middle turbinate = convexity of turbinate directed toward lateral nasal wall (10–26%)
    • Deviation of uncinate process
    • These conditions are not disease states per se!
Facial buttresses
  • = areas of relatively increased bone density that support functional units of the face (muscles, eyes, dental occlusion, airways)
    • of sufficient bone thickness to accomodate metal screw fixation
    • linked directly / through another buttress to cranium / skull base
  • horizontal buttresses
    • responsible for facial height
    • Upper transverse maxillary buttress:
      • temporal squamosa → zygomatic arch → inferior orbital rim → nasofrontal junction
        Posterior extension: orbital floor
        P.368

        Facial Butresses
    • Lower transverse maxillary buttress:
      • maxilla above alveolar ridge
        Posterior extension: hard palate
    • Upper transverse mandibular
    • Lower transverse mandibular
  • vertical buttresses
    • responsible for facial profile and width
    • Medial maxillary buttress:
      • anterior nasal spine → rim of piriform aperture → frontal process of maxilla → nasofrontal junction → frontal bone
        Posterior projection: medial orbital wall
        Anterior projection: lateral nasal wall
    • Lateral maxillary buttress:
      • above posterior maxillary molar → zygomaticomaxillary suture → body of zygoma → lateral orbital rim → zygomaticofrontal suture → frontal bone
        Posterior projection: lateral orbital wall, lateral wall of maxillary sinus
    • Posterior maxillary buttress:
      • pterygomaxillary junction
    • Posterior vertical buttress
Branchial Cleft Development
  • — 6 paired branchial arches are responsible for formation of lower face + neck; recognizable by 4th week GA
  • — each branchial arch contains a central core of cartilage + muscle, a blood vessel, and a nerve
  • — 5 ectodermal “clefts” / grooves on outer aspect of neck + 5 endodermal pharyngeal pouches separate the 6 arches with a closing membrane located at the interface between pouches and clefts
    Formation: during 4th–6th week of embryonic development
1st Branchial Arch = maxillomandibular arch
  • large ventral / mandibular prominence
    forms: mandible, incus, malleus, muscles of mastication
  • small dorsal / maxillary prominence
    forms: maxilla, zygoma, squamous portion of temporal bone, cheek, portions of external ear
    nerve: mandibular division of trigeminal nerve (V3)
    pouch forms: mastoid air cells + eustachian tube
    cleft forms: external auditory canal + tympanic cavity
    Branchial Apparatus
2nd Branchial Arch = hyoid arch
nerve: facial nerve (VII)
arch forms: thyroid gland, stapes, portions of external ear, muscles of facial expression
pouch forms: palatine tonsil + tonsillar fossa
  • cleft involutes completely by 9th fetal week; 2nd arch overgrows 2nd + 3rd + 4th clefts to form cervical sinus, which creates a tract that runs from the supraclavicular area just lateral to carotid sheath, turns medially at mandibular angle between external + internal carotid artery, and terminates in tonsillar fossa
3rd Branchial Arch
  • sinks into retrohyoid depression
    nerve: glossopharyngeal nerve
    arch forms: glossoepiglottic fold, superior constrictor m., internal carotid a., parts of hyoid bone
  • pouch forms:
    • thymus gland, which descends into mediastinum by 9th fetal week
    • inferior parathyroid glands passing down with the thymus
4th Branchial Arch
  • sunk into retrohyoid depression
    nerve: superior laryngeal branch of vagus nerve
    arch forms: epiglottis + aryepiglottic folds, thyroid cartilage, cricothyroid m., left component of aortic arch, right component of right proximal subclavian a.
    pouch forms: superior parathyroid glands, apex of piriform fossa
    cleft forms: ultimobranchial body, which provides parafollicular = “C” cells of thyroid
P.369

5th + 6th Branchial Arches
  • cannot be recognized externally
    nerve: recurrent laryngeal branch of vagus nerve
Oral cavity
  • comprises lip, upper + lower gingiva, buccal mucosa, hard palate, floor of mouth, anterior 2/3 of tongue
Oropharynx
  • consists of
    • pharyngeal wall between nasopharynx + pharyngoepiglottic fold
    • soft palate
    • tonsillar region
    • tongue base
  • Borders:
    • superior: soft palate and Passavant ridge (= ridge of pharyngeal muscle that opposes the soft palate when soft palate is elevated)
    • anterior: plane that joins the posterior border of soft palate, anterior tonsillar pillars, circumvallate papillae
    • posterior: posterior pharyngeal wall
    • inferior: vallecula
    • lateral: tonsillar region consisting of anterior tonsillar pillar (= palatoglossus muscle) + palatine / faucial tonsil + posterior tonsillar pillar (= palatopharyngeus muscle)
Hypopharynx
  • = compartment of aerodigestive tract between hyoid bone + inferior aspect of cricoid cartilage
  • Pyriform sinuses
    • = two symmetric lateral stalactites of air hanging from hypopharynx behind larynx
      • — inferior wall: level of cricoarytenoid joint
      • — anteromedial wall: lateral wall of aryepiglottic fold
      • — lateral wall: abuts posterior ala of thyroid cartilage
      • — posterior wall: most lateral aspect of posterior hypopharyngeal wall
    • Postcricoid area = pharyngoesophageal junction extends from level of arytenoid cartilages to inferior border of cricoid cartilage
    • — anterior wall of hypopharynx = posterior wall of lower larynx = “party wall”
  • Posterior hypopharyngeal wall
    • extends from level of valleculae to cricoarytenoid joints
Larynx
Vertical length: 44 mm (males), 36 mm (females), at 4th–6th cervical vertebrae
Supraglottis
  • extends from tongue base + valleculae to laryngeal ventricle
  • Vestibule = airspace within supraglottic larynx
  • Epiglottis
    • = leaf-shaped cartilage that functions as a lid to endolarynx
    • petiole = stem of epiglottis
    • thyroepiglottic ligament = connects petiole to thyroid cartilage inferiorly
    • hyoepiglottic ligament = connects epiglottis to hyoid bone anteriorly, covered by a mucosal fold between the valleculae (glossoepiglottic fold)
    • “free margin” = superior portion of epiglottis
  • False vocal cords
    • = ventricular folds = inferior continuation of aryepiglottic folds = mucosal surface of ventricular ligaments; forming superior border of laryngeal ventricle
  • Arytenoid cartilages
  • Aryepiglottic folds
    • = mucosal reflections between cephalad portion (= arytenoid processes) of arytenoid cartilage + inferolateral margin of epiglottis
    • soft-tissue folds forming border between lateral pyriform sinuses + central laryngeal lumen
  • Laryngeal ventricle
    • = fusiform fossa bounded by crescentic edge of false cords superiorly + straight margin of true cords inferiorly
    • generally not visible on axial scans
  • Preepiglottic space
    • low-density tissue between anterior margin of epiglottis + thyroid cartilage
  • Paralaryngeal space
    • low-density tissue between true + false cords and thyroid cartilage
    • continuous with preepiglottic space anteriorly + aryepiglottic folds superiorly
Glottis
  • True vocal cords
    • = extend from vocal process of arytenoid cartilage to anterior commissure
    • vocal cords adduct during phonation of “E” / breath holding
  • Anterior commissure
    • = midline laryngeal mucosa covering anterior portions of the true vocal cords where they abut the laryngeal surface of the thyroid cartilage
    • <1 mm soft tissue behind thyroid cartilage (during abduction of vocal cords with quiet breathing)
  • Posterior commissure
    • = midline laryngeal mucosal surface between attachment of true vocal cords to the arytenoid cartilages
Subglottis
  • extends from undersurface of true vocal cords to inferior surface of cricoid cartilage
    • Conus elasticus
      • = fibroelastic membrane extending from cricoid cartilage to medial margin of true vocal cords + forming lateral wall of subglottis
Deep Spaces of Suprahyoid Head & Neck
Masticator Space
  • = lateral to parapharyngeal space
  • Fascia:
    • superficial layer of deep cervical fascia encloses muscles of mastication
  • P.370

  • Contents:
    • muscles of mastication (medial + lateral pterygoid muscles, masseter, temporalis muscle)
    • ramus + body of mandible
    • cranial nerve V3
Pharyngeal Mucosal Space
  • adenoids, faucial + lingual tonsils
  • superior + middle constrictor muscles
  • salpingopharyngeal muscle
  • levator palatini muscle
  • torus tubarius
Parapharyngeal Space
  • = triangular-shaped centrally located space; major vertical highway extending from skull base to hyoid
  • Fascial borders:
    medial = middle layer of deep cervical fascia
    lateral = superficial layer of deep cervical fascia
    posterior = carotid sheath
  • Contents:
    • fat
    • internal maxillary artery
    • ascending pharyngeal artery
    • pharyngeal venous plexus
    • branches of cranial nerve V3
      Vectors: if parapharyngeal fat is effaced
      anteriorly = lesion in masticator space
      medially = lesion in pharyngeal mucosal space
      laterally = lesion in parotid space
      posteriorly = lesion in carotid space
      Transaxial Scan through Level of Lower Nasopharynx
Retropharyngeal Space
  • = potential space posterior to pharyngeal mucosal space + anterior to prevertebral space; major vertical highway from skull base to T4
  • Fascial borders:
    • mid + deep layers of cervical fascia; alar fascia laterally
  • Contents:
    • fat
    • medial + lateral retropharyngeal nodes
Prevertebral Space
  • = major highway from skull base to T4; posterior to retropharyngeal space
  • Fascial borders:
    • anterior compartment of deep cervical fascia:
      • from one transverse process to the other anteriorly in front of longus colli muscle
    • posterior compartment of deep cervical fascia:
      • from transverse process posteriorly to spinous process
  • Contents:
    • prevertebral muscles (longus colli)
    • scalene muscles
    • vertebral artery + vein
    • brachial plexus
    • phrenic nerve
P.371

Hyoid Bone Level
High Supraglottic Level
Mid Supraglottic Level
Low Supraglottic Level
Glottic Level
Undersurface of True Cord
Carotid Space
  • Carotid fascia extends from skull base to aortic arch
  • Contents:
    • below hyoid bone:
      • common carotid artery
      • internal jugular vein
      • cranial nerve X (vagus nerve)
      • cervical sympathetic plexus
    • at level of nasopharynx:
      • internal carotid artery
      • internal jugular vein
      • cranial nerves IX–XII
      • internal jugular chain of nodes
P.372

Parotid Space
  • Contents:
    • parotid gland with Stensen duct
    • intraparotid lymph nodes
    • external carotid + internal maxillary arteries
    • retromandibular vein
    • facial nerve
Submandibular Space
  • Contents:
    • submandibular gland with Wharton duct
    • facial artery + vein
    • cranial nerve XII
Temporal bone
  • SQUAMOUS PORTION
    • = lateral wall of middle cranial fossa + floor of temporal fossa
  • MASTOID PORTION
    • Mastoid antrum
    • Aditus ad antrum
      • connects epitympanum (= attic) of middle ear cavity to mastoid antrum
    • Körner septum
      • = small bony projection extending inferiorly from roof of mastoid antrum as part of petrosquamosal suture between lateral + medial mastoid air cells
  • PETROUS PORTION = inner ear
    • Tegmen tympani
      • = roof of tympanic cavity
    • Arcuate eminence
      • = prominence of bone over superior semicircular canal
    • Internal auditory canal (IAC)
      • Porus acusticus internus
        • = opening of internal auditory canal
      • Modiolus
        • = entrance to cochlea
      • Crista falciformis
        • = horizontal bony septum in IAC
    • Vestibular aqueduct
      • = transmits endolymphatic duct
    • Cochlear aqueduct
      • = transmits perilymphatic duct
    • Petrous apex
      • = separated from clivus by petro-occipital fissure + foramen lacerum
  • TYMPANIC PORTION
    • External auditory canal (EAC)
      • medial border formed by tympanic membrane, which attaches superiorly at scutum + inferiorly at tympanic annulus
  • STYLOID PORTION
Middle Ear
  • Borders:
    –anterior wall = carotid wall
    –posterior wall = mastoid wall including
    • facial nerve recess for descending facial nerve
    • pyramidal eminence for stapedius muscle
    • sinus tympani (clinically blind spot)
      –superior wall = tegmen tympani
      –inferior wall = jugular wall
      –lateral wall = tympanic membrane
      –medial wall = labyrinthine wall
  • EPITYMPANUM
    • = tympanic cavity above the line drawn between the inferior tip of scutum + tympanic portion of facial nerve
      Contents: malleus head, body + short process of incus, Prussak space (= area between incus + lateral wall of epitympanum)
  • MESOTYMPANUM
    • = tympanic cavity between inferior tip of scutum + line drawn parallel to inferior aspect of bony EAC
      Contents: manubrium of malleus, long process of incus, stapes, tensor tympani muscle (innervated by V3), stapedius muscle (innervated by VII)
  • HYPOTYMPANUM
    • = shallow trough in floor of middle ear
Inner Ear
  • Cochlea
    • 2 1/2 turns, basal first turn opens into round window posteriorly, encircles central bony axis of modiolus
  • Vestibule
    • = largest part of membranous labyrinth with subunits of utricle + saccule (not separately visualized); separated from middle ear by oval window
  • Semicircular canals
    • superior semicircular canal forms convexity of arcuate eminence
    • posterior semicircular canal points posteriorly along line of petrous ridge
    • lateral / horizontal semicircular canal juts into epitympanum
  • Cochlear aqueduct
    • contains 8-mm–long perilymphatic duct, extends from basal turn of cochlea to lateral border of jugular foramen paralleling IAC
      Function: regulates CSF + perilymphatic fluid pressure
  • Vestibular aqueduct
    • encompasses endolymphatic duct, extends from vestibule to endolymphatic sac
      Function: equilibration of endolymphatic fluid pressure
Parotid Gland
  • Embryology:
    • glandular component arises from ingrowth of local proliferation of oral epithelium, which creates ducts by 10th week GA; secretions begin by 18th week GA
    • Epithelial buds branch around divisions of facial nerve thus incorporating it into parotid parenchyma
    • The only salivary gland to become encapsulated after development of lymphatic system resulting in intraglandular lymph nodes and lymph vessels
      Location: wraps around mandibular angle (within parotid space)
      P.373

      Coronal Tomogram of Temporal Bone
      Axial Tomogram of Temporal Bone
      Coronal Scan of Normal Right Ear
      Axial Scan of Normal Right Ear
  • P.374

  • Anatomic divisions:
    • superficial lobe = main bulk of gland superficial and posterior to masseter muscle; separated by facial nerve from:
    • deep lobe = small extension of gland deep to angle of mandible
    • accessory lobe (20%) = superficial and lateral to masseter muscle + anterior to superficial lobe draining directly into parotid duct
      Drainage route: Stensen duct exiting above upper 2nd molar tooth
Thyroid Gland
CT values: 70–120 HU
Thyroxin-binding Globulin
  • ELEVATION OF TBG
    • Pregnancy
    • Estrogen administration
    • Genetic trait
  • REDUCTION IN TBG
    • Androgens
    • Anabolic steroids
    • Glucocorticoids
    • Nephrotic syndrome
    • Chronic hepatic disease
  • INHIBITION OF T4 BINDING TO TBG: salicylates
Parathyroid glands
Embryology: parathyroid glands develop by 6 weeks GA + migrate into neck at 8 weeks
Size: 6 × 4 × 1 mm = 25–40 mg
  • SUPERIOR PARATHYROID GLANDS
    Embryology: derived from 4th pharyngeal pouches, descending together with thyroid gland in close relationship to its posterolateral lobes
    Location: superior dorsal surface of thyroid gland / intrathyroidal
  • INFERIOR PARATHYROID GLANDS
    Embryology: derived from 3rd pharyngeal pouches migrating caudally with thymus
    Location: anywhere near / in thyroid, carotid bifurcation, lower neck, mediastinum
  • SUPERNUMERARY PARATHYROID GLANDS
    • 5th / 6th gland may occupy an ectopic site
    • Up to 12 parathyroids may be present!
  • Surgical success rates for finding parathyroid glands:
    • — 95% for initial cervical exploration
    • — 60% for repeat surgical exploration
      Cause for failure: overlooking an adenoma, multiple abnormal glands, diffuse hyperplasia
  • Localization technique:
    • US (75% sensitivity), thallium-technetium subtraction scintigraphy, MR (88% sensitivity)
Thyroxin T4 4.5–12.0 μg/dL
Triiodothyronine T3 90–200 ng/dL
Thyroid stimulating hormone TSH 0.4–4.5 μIU/mL
Free T4 (0.03% of T4) FT4 0.7–1.6 ng/dL
Free T3 (0.4% of T3) FT3 230–420 ng/L
Thyroxin-binding globulin TBG binds 70% of T4
    binds 38% of T3
Thyroxin-binding prealbumin TBPA binds 10% of T4
    binds 27% of T3
Albumin   binds 20% of T4
    binds 35% of T3
Radioiodine uptake RAIU 8–35% @ 24 h
Temporomandibular Joint (closed mouth position)
P.375

Criteria External Carotid Artery Internal Carotid Artery
Size usually smaller than ICA usually larger than ECA
Location oriented medially + anteriorly toward face oriented laterally + posteriorly toward mastoid process (mnemonic: IAC vis-á-vis ECA is positioned like helix vis-á-vis tragus of your ear)
Branches gives off arterial branches (superior thyroid artery as 1st branch) NO arterial branches
Waveform high-resistance flow pattern supplying capillary beds in skin + muscle: forward systolic component early diastolic flow reversal, occasionally followed by another component little / no flow in late diastole low-resistance waveform pattern supplying capillary bed in brain: high-velocity forward systolic component sustained strong forward flow in diastole stagnant eddy with flow reversal opposite to flow divider in carotid bulb
Maneuver oscillations on temporal tap maneuver  
Tooth Numbering System for Permanent Arch (according to American Dental Association)
P.376

Ear, Nose, and Throat Disorders
Adenoid Cystic Carcinoma
= CYLINDROMA
Incidence: 4–15% of all salivary gland tumors
Histo: (a) cribriform subtype, grade 1
(b) tubular subtype, grade 2
(c) solid/basaloid subtype, grade 3
♢ Perineural invasion is typical!
Age: 3rd–9th decade; maximum between 40 and 70 years; M = F
Location:
  • @ Minor salivary glands (most common; 25–31% of malignant neoplasms in minor salivary glands)
    • Most common tumor of the minor salivary glands!
    • • nasal obstruction + swelling
    Site: oral cavity > pharynx > nose > paranasal sinuses > trachea > larynx
  • @ Submandibular gland (15% of tumors in this gland)
  • @ Parotid gland (2–6% of tumors in this gland; arises from peripheral parotid ducts with propensity for perineural spread along facial nerve)
    • • hard mass + facial nerve pain/paralysis
    • infiltrating parotid mass
MR:
  • hypo- to hyperintense (high signal corresponds to low cellularity with a better prognosis) on T2WI
Metastases to: lung, cervical lymph nodes, bone, liver, brain
Prognosis: slow growing but relentless malignant course with repeat recurrences; the greater the cellularity, the worse the prognosis (requires entire tumor); 60–69% 5-year survival rate; 40% 10-year survival rate
Rx: repeat surgical excision + radiation therapy
Laryngeal Adenoid Cystic Carcinoma
0.25–1% of all malignant laryngeal tumors
Histo: uniform small basaloid cells with large deeply staining ovoid nuclei arranged in anastomosing cords or islands
  • coughing attacks, wheezing, hemoptysis
  • paralysis of recurrent laryngeal nerve due to propensity to invade nerves (CHARACTERISTIC)
  • absent history of cigarette smoking
Location: subglottis at junction with trachea (80%)
  • extensive submucosal tumor spread of entire larynx
  • invasion of cricoid cartilage, thyroid + esophagus
  • regional neck nodes hardly ever involved
Angiolipoma of parotid gland
= benign nodular lesion similar to ordinary lipomas except for associated angiomatous proliferation
Age: rare before puberty
CT:
  • circumscribed (more common)/infiltrating mass
  • marked enhancement around fatty components
DDx: hemangioma with fatty degeneration
Apical petrositis
= PETROUS apicitis
Frequency: chronic > acute apicitis
Etiology: spread from middle ear + mastoid infection; requires presence of air cells in petrous apices (which is found in 30% of population)
Organism: Pseudomonas, Enterococcus
  • Gradenigo syndrome = otorrhea (otitis media) + retro-orbital pain (trigeminal pain) + 6th nerve palsy
  • air cell opacification (fluid in ipsilateral middle ear + mastoid)
  • bone destruction (osteomyelitis)
MR:
  • enhancing mass about petrous tip
Cx: epidural abscess; cranial nerve palsy (abducens, trigeminal, vagus)
Mortality: up to 20% (prior to antibiotic era)
Rx: intravenous antibiotics, myringotomy, surgery
Branchial Cleft Anomalies
= failure of involution of branchial clefts leads to branchial cleft cysts/fistula/sinus tracts
First Branchial Cleft Cyst (5–8%)
= PAROTID LYMPHOEPITHELIAL CYST
Residual embryonic tract begins near submandibular triangle
  • + ascends through the parotid gland, terminates at junction of cartilaginous + bony external auditory canal
Incidence: 5–8% of all branchial cleft anomalies (rare)
Age: middle-aged women
  • enlarging mass near lower pole of parotid gland
  • recurrent parotid abscesses
  • ± facial nerve palsy
  • otorrhea (if cyst drains into EAC)
Pathologic classification (Work):
Type I duplication anomaly of membranous EAC; derived from ectoderm + lined with squamous epithelium; course parallel to EAC; medial to concha of ear; no skin appendages
Type II cyst arises from 1st branchial cleft containing ectoderm and mesoderm involving EAC + pinna; skin appendages (hair follicles, sweat and sebaceous glands)
  • cystic mass within gland or immediate periparotid region (superficial to/deep to parotid gland)
  • may extend into adjacent fat-containing parapharyngeal space ± connection to EAC
DDx: inflammatory parotid cyst, benign cystic parotid tumor, necrotic metastatic lymphadenopathy
Second Branchial Cleft Cyst (95%)
= incomplete obliteration of 2nd branchial cleft tract (cervical sinus of His) resulting in sinus tract/fistula/cyst (75%)
Incidence: 95% of all branchial cleft anomalies
Age: 10–40 years; M = F
Classification (Bailey):
Type I along anterior surface of sternocleido-mastoid muscle, just deep to platysma
Type II along anterior surface of sternocleido-mastoid muscle, lateral to carotid space, posterior to submandibular gland adhering to the great vessels (most common)
Type III extension medially between bifurcation of external and internal carotid arteries to lateral pharyngeal wall
Type IV within pharyngeal mucosal space
P.377

Path: 1–10-cm large thin-walled cyst, lined by stratified squamous epithelium overlying lymphoid tissue, filled with turbid yellowish fluid ± cholesterol crystals
  • history of multiple parotid abscesses unresponsive to drainage + antibiotics
  • otorrhea (if connected to external auditory canal)
Location:
  • anywhere along a line from the oropharyngeal tonsillar fossa to supraclavicular region of neck; classically at anteromedial border of sternocleidomastoid muscle + lateral to carotid space + at posterior margin of submandibular gland; may be in parapharyngeal space (after extension through stylomandibular tunnel + middle constrictor muscle)
  • oval/round cyst near mandibular angle
  • displacement of sternocleidomastoid muscle posteriorly, carotid artery + jugular vein posteromedially, submandibular gland anteriorly
  • cyst may enlarge after upper respiratory tract infection/injury
US:
  • compressible mass ± internal debris (due to hemorrhage/infection) obscuring its cystic nature
  • lack of internal flow
CT/MR:
  • “beak sign” = curved rim of tissue pointing medially between internal + external carotid arteries (PATHOGNOMONIC)
  • slight enhancement of capsule
DDx: necrotic neural tumor, cervical abscess, submandibular gland cyst, cystic lymphangioma, necrotic metastatic/inflammatory lymphadenopathy
Third Branchial Fistula/Cyst
= above superior laryngeal nerve
Incidence: extremely rare
Internal opening: piriform sinus anterior to fold formed by internal laryngeal nerve
Course: pierces thyrohyoid membrane, runs over hypoglossal nerve + under glossopharyngeal nerve, between internal + external carotid arteries, caudolateral/posterolateral to proximal internal + common carotid arteries
External opening: at base of neck anterior to sternocleidomastoid muscle
  • unilocular cystic mass within posterior cervical space
Fourth Branchial Fistula
= below superior laryngeal nerve
Incidence: extremely rare (R > L)
Internal opening: apex of piriform sinus
Course: between cricoid + thyroid cartilage, below cricothyroid muscle, caudal course between trachea + carotid vessels, deep to clavicle into mediastinum, looping forward below aorta (left side)/right subclavian artery (right side), ascending along ventral surface of common carotid artery, passing over hypoglossal nerve
External opening: at base of neck anterior to sternocleidomastoid muscle + anteroinferior to subclavian artery
  • recurrent episodes of “suppurative thyroiditis’”/neck abscesses
Site: 90% on left side
Carotid Artery Aneurysm
= aneurysm of extracranial carotid artery
Etiology:
  • Trauma
  • Infection (mycotic aneurysm)
  • Congenital (very rare): manifestation of connective tissue disorder (Ehlers-Danlos, Marfan, Kawasaki, Mafucci syndrome)
Carotid Artery Stenosis
= High-grade ICA stenosis is associated with increased risk for TIA, stroke, carotid occlusion, embolism arising from thrombi forming at site of narrowing
Increased risk for stroke:
  • significant ICA stenosis (compromised blood flow):
    • Reduction of blood flow occurs at 50–60% diameter stenosis/75% area stenosis
    • 2% risk of stroke with nonsignificant stenosis
    • 16% incidence of stroke with significant stenosis
    • 2% incidence of subsequent stroke following endarterectomy
  • intraplaque hemorrhage (embolic stroke)
Histo:
  • arteriosclerosis = generic term for all structural changes resulting in hardening of the arterial wall
  • Diffuse intimal thickening
    • = growth of intima through migration of medial smooth muscle cells into subendothelial space through fenestrations in internal elastic lamella associated with increasing amounts of collagen, elastic fibers, glycosaminoglycans
    Age: beginning at birth slowly progressing to adult life
  • Atherosclerosis
    • = intimal pool of necrotic, proteinaceous + fatty substances within hardened arterial wall
    Location: large + medium-sized elastic and muscular arteries
    • fatty streak = superficial yellow-gray flat intimal lesion characterized by focal accumulation of subendothelial smooth muscle cells + lipid deposits
    • fibrous plaque = whitish protruding lesion consisting of central core of lipid + cell debris surrounded by smooth muscle cells, collagen, elastic fibers, proteoglycans; a fibrous cap separates the lipid core (= atheroma) from the vessel lumen
    • P.378

    • complicated lesion = fibrous plaque with degenerative changes such as calcification, plaque hemorrhage, intimal ulceration/rupture, mural thrombosis
    • Plaque hemorrhage from thin-walled blood vessels in vascularized plaque may cause ulceration, thrombosis
      • + embolism, and luminal narrowing
      • In 93% of symptomatic patients
      • In 27% of asymptomatic patients
    • Plaque ulceration exposes thrombogenic subendothelial collagen + lipid-rich material
      • Frequent in plaques occupying >85% of lumen
      • 12.5% stroke incidence per year
  • Mönckeberg sclerosis = medial calcification
  • Hypertensive arteriosclerosis
Temporal course of carotid artery stenosis:
  • Stable stenosis (68%)
  • Progressive stenosis to >50% diameter reduction (25%)
Angiography:
  • @ Extracranial
    • smooth asymmetrical excrescence encroaching upon vessel lumen
    • crater/niche = ulceration
    • mound within base of crater = mural thrombus
    • Holman carotid slim sign = diffuse narrowing of entire ICA distal to high-grade stenosis due to decrease in perfusion pressure
    • occlusion of ICA
  • @ Intracranial
    • carotid siphon stenosis
    • retrograde flow in ophthalmic artery filled from ECA
    • small vessel occlusion
    • focal areas of slow flow
    • early draining vein = reactive hyperemia = “luxury perfusion” due to shunting between arterioles + venules surrounding an area of ischemia
    • ICA-MCA slow flow = delayed arrival + washout of ICA-MCA distribution in comparison to ECA
Carotid endarterectomy:
Benefit: 17% reduction of ipsilateral stroke at 2 years in patients with >70% carotid stenosis (NASCET = North American Symptomatic Carotid Endarterectomy Trial)
Risk: 1% mortality; 2% risk of intraoperative neurologic deficit
Predilection Sites of Arterial Stenosis
  Incidence of Lesions
  Stenosis Occlusion
Right ICA origin 33.8% 8.6%
Left ICA origin 34.1% 8.7%
Right vertebral artery origin 18.4% 4.8%
Left vertebral artery origin 22.3% 2.2%
Right carotid siphon 6.7% 9.0%
Left carotid siphon 6.6% 9.2%
Basilar artery 7.7% 0.8%
Right MCA 3.5% 2.2%
Left MCA 4.1% 2.1%
Carotid Duplex Ultrasound
Decrease in Luminal diameter vs. Cross-sectional area
Decrease in Lumen Diameter Decrease in Cross-sectional Area
20% 36%
40% 64%
60% 84%
80% 96%
Indications for carotid duplex US:
  • Screening for suspected extracranial carotid disease
    • high-grade flow-limiting stenosis
    • low-grade stenosis with hemorrhage
  • Nonhemispheric neurologic symptomatology
  • History of transient ischemic attack/stroke
  • Asymptomatic carotid bruit
  • Retinal cholesterol embolus
  • Preoperative evaluation before major cardiovascular surgery
  • Intraoperative monitoring of vascular patency during endarterectomy
  • Sequential evaluation after endarterectomy
  • Monitoring of known plaque during medical treatment
Grading of Internal Carotid Stenosis
= severity of stenosis is primarily graded as a ratio of lumen diameter narrowing NOT reduction in cross sectional area
Limitations:
  • Calcifications >1 cm in length
    • A jet associated with a >70% stenosis usually travels at least 1 cm downstream!
  • Contralateral high-grade stenosis
    • = ipsilateral ICA functions as collateral with increased blood flow velocities
    • Use velocity ratios to compensate for this effect!
  • Tortuosity
    image
    P.379

    image
  • Increased depth of artery
  • “High” bifurcation
Accuracy of duplex scans (in comparison to arteriography for ICA lesions):
  • 91–94% sensitivity, 85–99% specificity, 90–95% accuracy for >50% ICA diameter stenosis
  • NORMAL
    • no evidence of plaque
    • peak systolic velocity (PSV) < 125 cm/sec
    • no spectral broadening (clear window under systole)
  • MINIMAL DISEASE (0–15% diameter reduction)
    • minimal amount of plaque
    • PSV < 125 cm/sec
    • minimal spectral broadening in deceleration phase of systole
  • MODERATE DISEASE (16–49% diameter reduction)
    • moderate amount of plaque
    • peak systole <125 cm/sec
    • end-diastolic velocity (EDV) <40 cm/s
    • poststenotic spectral broadening throughout systole
  • SEVERE DISEASE = HEMODYNAMICALLY SIGNIFICANT LESION
    • 50–69% stenosis
      • PSV 125–230 cm/s
      • EDV 40–100 cm/s
    • >70% stenosis (benefit of endarterectomy documented in NASCET study)
      • peak systole >230 cm/s
      • end diastole >100 cm/s
      • peak systolic velocity ratio of ICA/CCA >4.0
  • CRITICAL STENOSIS (>95% diameter reduction)
    • PSV and EDV return to normal range/flow undetectable
    • “string sign” on color Doppler with slow-flow sensitivity setting
  • OCCLUSION
    • no signal in ICA on longitudinal/transverse images (color sensitivity + velocity scale must be set low enough to clearly discern flow signals within internal jugular vein)
    • absence of diastolic flow/diastolic flow reversal in CCA (high impedance flow)
    • increased diastolic flow in ECA (if ECA assumes the role of primary supplier of blood to brain)
    • increase in peak systolic velocities in contralateral ICA (due to collateral flow)
Common Carotid Waveform Analysis
  • DISTAL OBSTRUCTION
    • high-pulsatility waveform (pulsatility changes occur only with >80% stenosis)
    • reduced amplitude
  • PROXIMAL OBSTRUCTION
    • low-amplitude damped waveform
Hemodynamic Variations of Carotid Stenosis
Doppler Spectrum Analysis (Consensus Conference of Society of Radiologists in Ultrasound 2002)
Diameter Stenosis (%) ICA Peak Systolic Velocity (cm/s) ICA/CCA Peak Systolic Velocity Ratio ICA End-Diastolic Velocity (cm/s) Plaque
Normal <125 <2.0 <40 none
<50 <125 <2.0 <40 <50% diameter reduction
50—69 125—230 2.0—4.0 40—100 ≥50% diameter reduction
>70 >230 >4.0 >100 ≥50% diameter reduction
Critical stenosis low/undetectable variable variable massive, detectable lumen
Occlusion undetectable not applicable undetectable no detectable lumen
  • MORPHOLOGY OF STENOSIS
    • Degree of stenosis: velocities increase up to a luminal diameter of 1.0–1.5 mm
    • Length of stenosis: peak velocities decrease with length of stenosis
    • use the same angle + steering direction when following a patient for disease progression
  • PHYSIOLOGIC VARIABILITY
    • A range of velocities may be encountered with a given degree of stenosis!
    • P.380

    • ICA/CCA ratio obviates effects of physiologic variability!
    • Compare left with right waveforms to avoid errors!
    • Measure volume flow (more sensitive because of contralateral compensatory flow increase)
Cause:
  • Cardiac output
  • Pulse rate
  • Flow velocity: increased with obstruction in collateral vessels, decreased with proximal obstruction in same vessel
  • Normal helical nature of blood flow with many different velocity vectors + nonaxial blood flow not detectable by color Duplex imaging
  • Peripheral resistance
  • Arterial compliance
  • Hypertension
  • Blood viscosity
Carotid Plaque
  • Asymptomatic patients
    • with diffuse atherosclerotic disease
    Prevalence of >50% stenosis: 18–20%
  • Symptomatic patients:
    • with stroke, TIA, amaurosis fugax as a result of emboli from atheromas at the carotid bifurcation
    Prevalence of >50% stenosis: 14%
Formation Theory of Carotid Plaque
  • Stagnant eddy that rotates at outer vessel margin (opposite to the flow divider in area of flow separation + low shear stress) leads to net influx of fluid into subendothelial tissue with progressive deposition of lipids + smooth muscle cell proliferation
  • Increased likelihood of intraplaque hemorrhage (vascularization of plaque with fragile vessels derived from vasa vasorum/from lumen) + fissuring from a critical size on
    • As the degree of stenosis increases, it is more likely that plaques become denser + more heterogeneous demonstrating an irregular surface!
Density of Carotid Plaque
  • Hypoechoic = low-echogenicity plaque
    • = fibrofatty plaque/hemorrhage
    • echogenicity less than sternocleidomastoid muscle
    • flow void/flow disturbance on color Duplex
  • Isoechoic plaque
    • = smooth muscle cell proliferation/laminar thrombus
    • echogenicity equal to sternocleidomastoid muscle + lower than adventitia
  • Hyperechoic = moderately echogenic plaque
    • = fibrous plaque
    • echogenicity higher than sternocleidomastoid muscle + similar to adventitia
  • Calcification = strongly echogenic plaque
    • acoustic shadow impairs visualization of intima
Texture of Carotid Plaque
  • Homogeneous plaque = stable plaque
    Histo: deposition of fatty streaks + fibrous tissue; rarely shows intraplaque hemorrhage/ulcerations
    • Prognosis:
      • Neurologic deficits develop in 4%
      • Ipsilateral infarction on CT in 12%
      • Ipsilateral symptoms develop in 22%
      • Progressive stenosis develops in 18%
    • homogeneous uniform echo pattern with smooth surface (acoustic impedance similar to blood)
  • Heterogeneous plaque
    • = unstable plaque = mixture of high, medium, and low-level echoes with smooth/irregular surface; may fissure/tear resulting in intraplaque hemorrhage/ulceration + thrombus formation (embolus/increasing stenosis)
    • B-mode ultrasound has 90–94% sensitivity, 75–88% specificity, 90% accuracy for intraplaque hemorrhage
    Histo: lipid-laden macrophages, monocytes, leukocytes, necrotic debris, cholesterol crystals, calcifications
    • Prognosis:
      • Neurologic deficits develop in 27%
      • Ipsilateral infarction on CT in 24%
      • Ipsilateral symptoms develop in 50%
      • Progressive stenosis develops in 77%
    • anechoic areas within plaque (= hemorrhage/lipid deposition/focal plaque degeneration)
    • heterogeneous complex echo pattern
Surface Characteristics of Carotid Plaque
  • = US unreliable due to poor visualization of intima
Categories: — smooth
— mildly irregular
— markedly irregular
— ulcerated
  • Intimal thickening
    Histo: fatty streaks
    • wavy/irregular line paralleling vessel wall extending >1 mm into vessel lumen
  • Ulcerated plaque
    Accuracy: 60% sensitive, 60–70% specific
    • The presence of intraplaque hemorrhage is much more common than normally appreciated
    • Neither arteriography nor US has proved reliable!
    • isolated crater of >2 mm within surface of plaque demonstrated on transverse + longitudinal images
    • reversed flow vortices extending into plaque crater demonstrated by color Doppler
    • proximal + distal undercutting of plaque
    • anechoic area within plaque extending to surface
Errors In Duplex Ultrasound
  • Error in proper localization of stenosis (6%)
    Cause: ECA stenosis placed into ICA/carotid bifurcation or vice versa
  • Mistaking patent ECA branches for carotid bifurcation (4%)
    P.381

    Cause: complete occlusion of ICA not recognized
    • disparity in position of bifurcation
    • no difference in pulsatility waveform
    • high-resistance waveform in CCA
  • Interpreter error in estimating severity of stenosis (2.5%):
    • usually overestimation, rarely underestimation
    • absence of one/more components for diagnosis which are
      • significant elevation of peak velocity
      • poststenotic turbulence
      • extension of high velocity into diastole
  • Superimposition of ECA + ICA (2%)
    Cause: strict coronal orientation of ECA + ICA
    • superimposition can be avoided by rotation of head to opposite side
  • Severe stenosis mistaken for occlusion
    • minimal flow not detectable
    • angiogram necessary with delayed images
  • Weak signals misinterpreted as occlusion
  • Normal/weak signals in severe stenosis
    Cause: severe stenosis causes a decrease in blood flow + peak velocity with return to normal velocity levels
    • high resistivity in CCA
  • Point of maximum frequency shift not identified
    Cause: extremely small lumen/short segment of stenosis
    • unexplained (poststenotic) coarse turbulence
    • ipsilateral ECA collateral flow
    • abnormal CCA resistivity
  • Stenosis obscured by plaque/strong Doppler shift in overlying vessel
  • Inaccessible stenosis
    • abnormal CCA resistivity
    • abnormal oculoplethysmography
  • Unreliable velocity measurements
    • higher velocities: hypertension, severe bradycardia, obstructive contralateral carotid disease, anemia, hyperthryoidism
    • lower velocities: arrhythmia, aortic valvular lesion, CHF, severe cardiomyopathy, proximal obstructive carotid lesion (“tandem lesion”), >95% ICA stenosis
    • aliasing = high velocities are displayed in reversed direction below zero baseline due to Doppler frequency exceeding half the pulse repetition frequency
      Remedy: shift zero baseline, increase pulse repetition frequency, increase Doppler angle, decrease transducer frequency, use continuous-wave Doppler probe
Cervical dermoid/epidermoid cyst
Location: floor of mouth
  • Cystic teratoma
    • teratoma = neoplasm whose tissue is foreign to the part of the body from which the tumor arises
    • epidermoid cyst = epidermal inclusion cyst
      • = lined by simple squamous epithelium without skin appendages
    • dermoid cyst
      • = epithelial-lined cyst containing hair follicles + sebaceous + sweat glands
    • teratoid cyst
      • = lined with squamous/respiratory epithelium containing derivatives of ectoderm + endoderm + mesoderm (skin appendages, nervous/GI/respiratory tissue)
  • Nonteratomatous sequestration-type epithelial-lined cyst
    Location:
    • dorsum of nose in infants (most common)
    • midline anterior floor of mouth:
      • sublingual between mylohyoid muscle + tongue (DDx: inclusion cyst, ranula)
      • submental between platysma + mylohyoid muscle
Choanal Atresia
Most common cause of neonatal nasal obstruction!
Frequency: 1:5,000 to 1:8,000 neonates; M < F
Etiology: failure of perforation of oronasal membrane, which normally perforates by 7th week EGA
Associated with other anomalies in 50–75%:
  • acrophalyngosyndactyly, amniotic band syndrome, malrotation of bowel, Crouzon syndrome, fetal alcohol syndrome, DiGeorge syndrome, Treacher-Collins syndrome, chromosome 18/12 anomalies, polydactyly, coloboma, facial cleft, CHD, TE fistula, craniosynostosis
Location: bilateral: unilateral atresia = 3:2
  • respiratory distress in bilateral choanal atresia (relieved by crying in neonates who are obligate nose breathers during first 2–6 months)
  • nasal stuffiness, rhinorrhea, infection in unilateral choanal atresia
Types:
  • OSSEOUS/BONY SEPTATION (85–90%)
    Cause: incomplete canalization of choanae
  • MEMBRANOUS SEPTATION (10–15%)
    Cause: incomplete resorption of epithelial plugs
  • osseomembranous
CT (preceded by vigorous suctioning + administration of topical decongestant):
  • narrowing of posterior choanae to a width of <3.4 mm (in children <2 years of age)
  • inward bowing of posterior maxilla
  • fusion/thickening of vomer
  • bone/soft-tissue septum extending across the posterior choanae
Dx: nasal catheter cannot be advanced to beyond 32 mm
Cx: bilateral choanal atresia is life-threatening
Rx: endoscopic perforation, choanal reconstruction
Cholesteatoma
  • = keratoma
  • = epithelium-lined sac filled with keratin debris leading to bone destruction by pressure + demineralizing enzymes
Primary Cholesteatoma (2%)
  • = CONGENITAL CHOLESTEATOMA = EPIDERMOID CYST
  • P.382

  • = derived from aberrant embryonic ectodermal rests in temporal bone (commonly petrous apex)/epidural space/meninges
  • • conductive hearing loss in child with NO history of middle ear inflammatory disease
  • • cholesteatoma seen through intact tympanic membrane
Associated with: EAC dysplasia
Location:
  • epitympanum
  • petrous pyramid: internal auditory canal first involved
  • meninges: scooped out appearance of petrous ridge
  • cerebellopontine angle: erosion of porus, shortening of posterior canal wall
  • jugular fossa: erosion of posteroinferior aspect of petrous pyramid
Secondary Cholesteatoma (98%)
= INFLAMMATORY CHOLESTEATOMA = ACQUIRED EPIDERMOID
Cause:
  • ingrowth of squamous cell epithelium of EAC through tympanic membrane (= eardrum) secondary to
    • repeated episodes of ear inflammation with invagination of posterosuperior retraction pocket
    • marginal perforation of eardrum
Age: usually >40 years
  • whitish pearly mass behind intact tympanic membrane (invasion of middle ear cavity and mastoid) diagnosed otoscopically in 95%
  • facial paralysis (compression of nerve VII at geniculate ganglion)
  • conductive hearing loss (compromise of nerve VIII in internal auditory canal/involvement of cochlea or labyrinth)
  • severe vertigo (labyrinthine fistula)
Types:
  • Pars flaccida cholesteatoma = Primary acquired cholesteatoma = Attic cholesteatoma (most common)
    • increasing width of attic
    • initially destruction of lateral wall of attic, particularly the drum spur (scutum) with invasion of Prussak space
    • extension posteriorly through aditus ad antrum into mastoid antrum
    • destruction of Körner septum
  • Pars tensa cholesteatoma = Secondary acquired cholesteatoma (less frequent)
    • displacement of auditory ossicles
    • erosion of ossicular chain: first affecting long process of incus
  • nondependent homogeneous mass
  • perforation of tympanic membrane posterosuperiorly (pars flaccida = Shrapnell membrane)
  • poorly pneumatized mastoid (frequent association)
  • erosion of tegmen tympani (with more extensive cholesteatoma) producing an extradural mass
  • destruction of labyrinthine capsule (less common) involving the lateral semicircular canal first
  • erosion of facial canal
MRI:
  • iso-/hypointense relative to cortex on T1WI
  • no enhancement with Gd-DTPA (enhancement is related to granulation tissue)
Cx: (1) Intratemporal: ossicular destruction, facial nerve paralysis (1%), labyrinthine fistula, automastoidectomy, complete hearing loss
(2) Intracranial: meningitis, sigmoid sinus thrombosis, temporal lobe abscess, CSF rhinorrhea
DDx: chronic otitis media, granulation tissue
= cholesterol granuloma, brain herniation through tegmen defect, neoplasm (rhabdomyosarcoma, squamous cell carcinoma)
Cholesterol Granuloma
= CHOLESTEROL CYST
= acquired inflammatory lesion of petrous bone
Histo: cholesterol crystals surrounded by foreign-body giant cells; embedded in fibrous connective tissue with varying proportions of hemosiderin-laden macrophages, chronic inflammatory cells and blood vessels; brownish fluid contains cholesterol crystals + blood (= “chocolate cyst”)
  • • blue (vascular) tympanic membrane without pulsatile tinnitus
  • ossicles remain intact
CT:
  • nonenhancing middle ear mass
MRI:
  • hyperintense signal on T1WI + T2WI secondary to methemoglobin (DDx to cholesteatoma, which is isointense to brain on T1WI)
Chronic Recurrent Sialadenitis
  • painful periodic unilateral enlargement of parotid gland
  • milky discharge may be expressed
Sialography:
  • Stensen duct irregularly enlarged/sausage-shaped
  • pruning of distal parotid ducts
  • ± calculi
CT:
  • diffusely enlarged dense gland
  • dilated Stensen duct ± calculi
Cx: Mucocele
Cogan Syndrome
= AUTOIMMUNE INTERSTITIAL KERATITIS
MR:
  • membranous labyrinthine enhancement
Croup
  • = ACUTE LARYNGOTRACHEOBRONCHITIS = ACUTE VIRAL SPASMODIC LARYNGITIS
  • = lower respiratory tract infection
Organism: parainfluenza, respiratory syncytial virus
Age: >6 months of age, peak incidence 2–3 years
  • • history of viral lower respiratory infection
  • • hoarse cry + “brassy” cough
  • • inspiratory difficulty with stridor
  • • fever
  • thickening of vocal cords
  • P.383

  • NORMAL epiglottis + aryepiglottic folds
  • “steeple sign” = subglottic “inverted V” = symmetrical funnel-shaped narrowing 1–1.5 cm below lower margins of pyriform sinuses on AP radiograph (loss of normal “shouldering” of air column caused by mucosal edema + external restriction by cricoid), accentuated on expiration, paradoxical inspiratory collapse, less pronounced during expiration
  • narrow + indistinct subglottic trachea on lateral radiograph
  • inspiratory ballooning of hypopharynx (nonspecific sign of any acute upper airway obstruction)
  • distension of cervical trachea on expiration
    Prognosis: usually self-limiting
Dacryocystocele
  • 2nd most common cause of neonatal nasal obstruction (after choanal atresia)
Cause: obstruction of nasolacrimal duct (imperforate Hasner membrane distally, reason for proximal obstruction unknown)
  • • tense blue-gray mass at medial canthus/in nasal cavity
  • nasolacrimal duct dilatation
  • homogeneous well-defined mass of fluid attenuation
  • enhancement of thin wall
  • superior displacement of inferior turbinate bone
  • contralateral shift of nasal septum
Cx: dacryocystitis (postnatal infection with adjacent soft-tissue swelling + enhancement), periorbital cellulitis
Rx: duct massage, duct probing, prophylactic antibiotics
Dermoid Cyst of Neck
  • 7% of all dermoid inclusion cysts occur in the head and neck
Age: 2nd–3rd decades; M = F
Path: circumscribed encapsulated lesions, covered by squamous epithelium, lumen filled with cheesy keratinaceous + sebaceous material
Histo: epithelial-lined cyst containing hair follicles + sebaceous glands + sweat glands
  • slowly growing soft mobile mass in the suprahyoid midline (no movement with tongue protrusion!)
Location: lateral eye brow > floor of mouth (11%)
Site:
  1. sublingual space (superior to mylohyoid muscle) = intraoral surgical approach (more frequent)
  2. submandibular (inferior to mylohyoid muscle) = external surgical approach
Size: few mm–up to 12 cm
thin-walled unilocular mass
CT:
  • homogeneous fluid material of 0–18 HU
  • heterogeneous mass (due to various germinal components)
  • fluid-fluid level (due to supernatant lipid)
  • “sack-of-marbles” appearance (= coalescence of fat) is PATHOGNOMONIC
  • rim enhancement frequent
MR:
  • hypointense/hyperintense (sebaceous fluid)/isointense relative to muscle on T1WI
  • hyperintense on T2WI + internally heterogeneous
Prognosis: malignant degeneration into squamous cell carcinoma in 5%
DDx: ranula
Dissection of Cervicocephalic Arteries
  • = hematoma within media splitting off the vessel wall and causing a false lumen within media
Incidence: responsible for 5–20% of strokes in young and middle-aged adult
Location: cervical ICA (60%), vertebral artery (20%), both ICA + vertebral artery (10%); multiple simultaneous dissections (33%)
Site: (a) subintimal dissection = close to intima
(b) subadventitial dissection = close to adventitia
  • arterial narrowing/occlusion
  • intimal flap
  • pseudoaneurysm
  • embolic distal branch occlusion of intracranial artery
US (50% accuracy):
  • echogenic intimal flap
  • echogenic thrombus
  • dampened/high-resistance Doppler waveform
CECT:
  • narrowing/occlusion of contrast-filled artery
MR:
  • periarterial rim of hyperintense signal on T1WI + iso- to hyperintense on T2WI around flow void of artery (= intramural hematoma)
  • pseudoenlargement of external diameter of artery
Rx: early anticoagulant therapy (to prevent stroke)
Carotid Artery Dissection
  • Twice as common as vertebral artery dissection!
  • Etiology:
    • SPONTANEOUS CAROTID DISSECTION
      • nonrecalled minor/trivial trauma (frequent)
      • primary arterial disease (rare): Marfan syndrome. fibromuscular dysplasia (in 15%), cystic medial necrosis, collagen vascular disease, homocystinuria
      Associated with: hypertension (36%), smoking (47%), migraine (11%)
    • TRAUMATIC CAROTID DISSECTION (rare)
      • blunt/penetrating trauma (automobile accident, boxing, accidental hanging, diagnostic carotid compression, manipulative therapy)
    Associated with: fracture through carotid canal
    Incidence: 2–5–20% of strokes in persons aged 40–60 years
    Age: 18–76 years (66% between 35 and 50 years)
  • unremitting unilateral anterior headache (86%), neck pain (25%)
  • TIA/stroke (58%), amaurosis fugax (12%)
  • oculosympathetic paresis = Horner syndrome (52%)
  • bruit (48%)
    Location: cervical ICA usually at level of C1–2 (60%) within a few cm of carotid bifurcation > supraclinoid segment of ICA; bilateral carotid dissections (15%)
    Length: a few centimeters
Angiography:
  • string sign = elongated tapered irregular luminal stenosis extending to base of skull (76%)
  • P.384

  • abrupt luminal reconstitution at level of bony carotid canal (42%)
  • fingerlike/saccular aneurysm (40%), often in upper cervical/subcranial region
  • intimal flap (29%)
  • double-barrel lumen similar to aortic dissection (rare)
  • slow ICA-MCA flow
  • tapered “flamelike”/“radish taillike” occlusion (17%), often distal to carotid bulb
Cx: (1) Thromboemboli due to stenosis
(2) Subarachnoid hemorrhage (with intracranial location)
(3) Secondary aneurysm
Prognosis: complete/excellent recovery (8%) with normalization in a few months; worsening in 10%
Rx: best therapy not clear; anticoagulation (primary treatment), surgery, endovascular stent placement
Vertebral Artery Dissection
  • = hemorrhage into wall of vertebral artery
Prevalence: unknown; up to 15% of strokes in young adults
Etiology: (a) traumatic stretching of artery over lateral mass of C2 during rotation of head (chiropractic manipulation, bowling, tennis, archery)
(b) spontaneous
Predisposed: fibromuscular dysplasia, Marfan syndrome, collagen vascular disease, homocystinuria
  • headache: occipital (>50%), frontal (20%), orbital (20%)
  • neck pain (30%)
Location: at level of C1/2 (65%); bilateral vertebral artery dissections (5%); site of direct trauma
MR (modality of choice):
  • decreased arterial lumen
  • diminished flow void
  • periarterial rim signal intensity changes with time (hemoglobin)
Angio:
  • tapering of artery/intimal flap/complete occlusion
Cx: stroke (in up to 95%) after hours/weeks
Prognosis: full recovery with some residual deficit (88%)
Epiglottitis
  • ACUTE BACTERIAL EPIGLOTTITIS
  • life-threatening infection with edema of epiglottis + aryepiglottic folds
Organism: Haemophilus influenzae type B, Pneumococcus, Streptococcus group A
Age: >3 years, peak incidence 6 years
  • abrupt onset of respiratory distress with inspiratory stridor
  • severe dysphagia
Location: purely supraglottic lesion; associated subglottic edema in 25%
Lateral radiograph (frontal view irrelevant):
  • Radiograph should be taken in erect position only!
  • enlargement of epiglottis + thickening of aryepiglottic folds
  • circumferential narrowing of subglottic portion of trachea during inspiration
  • ballooning of hypopharynx + pyriform sinuses
  • cervical kyphosis
Cx: Mortal danger of suffocation secondary to hazard of complete airway closure; patient needs to be accompanied by physician experienced in endotracheal intubation
External Auditory Canal Dysplasia
Incidence: 1:10,000 births; family history in 14%
Etiology:
  • isolated
  • Trisomy 13, 18, 21
  • Turner syndrome
  • Maternal rubella
  • Craniofacial dysostosis
  • Mandibulofacial dysostosis
SPECTRUM
  • Stenosis of EAC
  • Fibrous atresia of EAC
  • Bony atresia (in position of tympanic membrane)
  • Decreased pneumatization of mastoid (mastoid cells begin to form in 7th fetal month)
  • Decreased size/absence of tympanic cavity
  • Ossicular changes (rotation, fusion, absence)
  • Ectopic facial nerve = anteriorly displaced vertical (mastoid) portion of facial nerve canal
  • Decrease in number of cochlear turns/absence of cochlea
  • Dilatation of lateral semicircular canal
  • bilateral in 29%; M:F = 6:4
  • pinna deformity
  • stenotic/absent auditory canal
    Cx: congenital cholesteatoma (infrequent)
Extramedullary Plasmacytoma
= Uncommon form; relatively benign course (dissemination may be found months/years later or not at all); questionable if precursor to multiple myeloma
Age: 35–40 years; M:F = 2:1
Location: air passages (50%) predominantly in upper nose and oral cavity; larynx; conjunctiva (37%); lymph nodes (3%)
  • • usually not associated with increased immunoglobulin titer or amyloid deposition
  • mass of one to several cm in size with well-defined lobulated border
Classification:
  • Medullary plasmacytoma
  • Multiple myeloma:
    • scattered involvement of bone
    • myelomatosis of bone
  • Extramedullary plasmacytoma
DDx:
  • MULTIPLE MYELOMA
    • = malignant course with soft-tissue involvement in 50–73%:
    • (a) microscopic infiltration
    • (b) enlargement of organs
    • (c) formation of tumor mass (1/3)
    • • usually associated with protein abnormalities
    • • may have amyloid deposition
    P.385

    Age incidence: 50–85 years
    • Tends to occur late in the course of the disease and indicates a poor prognosis (0–6% 5-year survival)
Fibromatosis Colli
= rare form of infantile fibromatosis that occurs solely in sternocleidomastoid muscle
Cause: in >90% associated with birth trauma during difficult delivery/forceps delivery
Path: compartment syndrome with pressure necrosis + secondary fibrosis of sternocleidomastoid m.
Age: 2nd to 4th weeks of life; M > F
  • history of difficult delivery (forceps)
  • firm soft-tissue mass in lower 1/3 of sternocleidomastoid muscle, which may grow over 2–4 additional weeks
  • torticollis (14–20%) due to muscle contraction
Location: lower 1/3 of sternocleidomastoid muscle affecting sternal + clavicular heads of the muscle; usually unilateral (R > L)
  • focal/diffuse enlargement of sternocleidomastoid m.
  • US:
    • homogeneously enlarged sternocleidomastoid m. without a focal lesion
    • well-/ill-defined mass within sternocleidomastoid muscle:
      • hypo- to iso- to hyperechoic mass depending on duration of disorder
  • MR:
    • diffuse abnormal high signal intensity (greater than that of fat) within muscle on T2WI
  • CT:
    • isoattenuating homogeneous muscle enlargement
Prognosis: gradual spontaneous regression by age 2 (in 66%) with/without treatment
Rx: (1) muscle stretching exercise
(2) surgery in 10%
DDx: (1) Neuroblastoma (heterogeneous solid mass with calcifications)
(2) Rhabdomyosarcoma
(3) Lymphoma (well-defined round /oval masses along cervical lymph node chain)
(4) Cystic hygroma (anechoic region with septations)
(5) Branchial cleft cyst
(6) Hematoma
Goiter
Adenomatous Goiter
  • = MULTINODULAR GOITER
  • US: (89% sensitive, 84% specific, 73% positive predictive value, 94% negative predictive value)
    • increased size + asymmetry of gland
    • multiple 1–4-cm solid nodules
    • areas of hemorrhage + necrosis
    • coarse calcifications may occur within adenoma (secondary to hemorrhage + necrosis)
  • Cx: compression of trachea
Diffuse Goiter
US:
  • increase in glandular size, R lobe > L lobe
  • NO focal textural changes
  • calcifications not associated with nodules
Iodine-deficiency Goiter
Not a significant problem in United States because of supplemental iodine in food
Etiology: chronic TSH stimulation
  • • low serum T4
  • high I-131 uptake
Jod-Basedow Phenomenon (2%)
  • = development of thyrotoxicosis (= excessive amounts of T4 synthesized + released) if normal dietary intake is resumed/iodinated contrast medium administered
Incidence: most common in individuals with longstanding multinodular goiter
Age: >50 years
  • multinodular goiter with in-/decreased uptake (depending on iodine pool)
Toxic Nodular goiter
  • PLUMMER DISEASE
  • = autonomous function of one/more thyroid adenomas
Peak age: 4–5th decade; M:F = 1:3
  • • elevated T4
  • • suppressed TSH
  • nodular thyroid with hot nodule + suppression of remainder of gland
  • stimulation scan will disclose normal uptake in remainder of gland
  • increased radioiodine uptake by 24 hours of approximately 80%
Rx: (1) I-131 treatment with empirical dose of 25–29 mCi (hypothyroidism in 5–30%)
(2) Surgery (hypothyroidism in 11%)
(3) Percutaneous ethanol injection (hypothyroidism in <1%, transient damage of recurrent laryngeal nerve in 4%)
Intrathoracic Goiter
  • = extension of cervical thyroid tissue/ectopic thyroid tissue (rare) into mediastinum
Incidence: 5% of resected mediastinal masses; most common cause of mediastinal masses; 2% of all goiters
  • • mostly asymptomatic
  • • symptoms of tracheal + esophageal + recurrent laryngeal nerve compression
  • Location:
    • retrosternal (80%) = in front of trachea
    • posterior descending (20%) = behind trachea but in front of esophagus, caudal extent limited by arch of azygos vein, exclusively on right side of trachea
  • continuity with cervical thyroid/lack of continuity (with narrow fibrous/vascular pedicle)
  • frequent focal calcifications
  • CT:
    • mass of high HU + well-defined margins
    • inhomogeneous texture with low-density areas (= degenerative cystic areas)
    • marked + prolonged enhancement
P.386

Graves Disease
  • = DIFFUSE TOXIC GOITER
  • = autoimmune disorder with thyroid-stimulating antibodies (LATS) producing hyperplasia + hypertrophy of thyroid gland
Peak age: 3rd–4th decade; M:F = 1:7
  • • elevated T3 + T4
  • • depressed TSH production
  • • dermopathy = pretibial myxedema (5%)
  • • ophthalmopathy = periorbital edema, lid retraction, ophthalmoplegia, proptosis, malignant exophthalmos
  • diffuse thyroid enlargement
  • uniformly increased uptake
  • incidental nodules superimposed on preexisting adenomatous goiter (5%)
US: (identical to diffuse goiter)
  • global enlargement of 2–3 × the normal size
  • normal/diffusely hypoechoic pattern
  • hyperemia on color Doppler
Rx: I-131 treatments (for adults):
Dose: 80–120 μCi/g of gland with 100% uptake (taking into account estimated weight of gland + measured radioactive iodine uptake for 24 hours)
Cx: 10–30% develop hypothyroidism within 1st year + 3%/year rate thereafter
HIV Parotitis
Histo: benign lymphoepithelial lesion consisting of an intranodal cyst lined with epithelial cells
US:
  • multiple hypoechoic/anechoic areas without posterior acoustic enhancement (70%)
  • anechoic cysts (30%)
CT/MR:
  • bilateral parotid gland enlargement with intraglandular cystic + solid masses
  • cervical lymphadenopathy + enlarged adenoids typically associated
Prognosis: parotid involvement is associated with a better prognosis in HIV-positive children!
Hypopharyngeal Carcinoma
Histo: squamous cell carcinoma
May be associated with:
  • Plummer-Vinson syndrome (= atrophic mucosa, achlorhydria, sideropenic anemia) affecting women in 90%
  • • sore throat, intolerance to hot/cold liquids (early signs)
  • • dysphagia, weight loss (late signs)
  • • cervical adenopathy (in 50% at presentation)
    Stage:
    T1 tumor limited to one subsite
    T2 tumor involves >1 subsite/adjacent site without fixation of hemilarynx
    T3 same as T2 with fixation of hemilarynx
    T4 invasion of thyroid/cricoid cartilage/soft tissue of neck
Pyriform Sinus Carcinoma
Incidence: 60% of hypopharyngeal carcinomas
  • • may escape clinical detection if located at inferior tip; often origin of “cervical adenopathy with unknown primary” (next to primaries in lingual + faucial tonsils and nasopharynx)
  • invasion of posterior ala of thyroid cartilage, cricothyroid space, soft tissue of neck in T4 lesion
Prognosis: poor due to early soft-tissue invasion
Postcricoid Carcinoma
Incidence: 25% of hypopharyngeal carcinomas
  • difficult assessment due to varying thickness of inferior constrictor + prevertebral muscles
Prognosis: 25% 5-year survival (worst prognosis)
Posterior Pharyngeal Wall Carcinoma
Incidence: 15% of hypopharyngeal carcinomas
  • invasion of retropharyngeal space with extension into oro- and nasopharynx
  • retropharyngeal adenopathy
Inverted Papilloma
= INVERTING PAPILLOMA = ENDOPHYTIC PAPILLOMA
  • = SQUAMOUS CELL PAPILLOMA = TRANSITIONAL CELL PAPILLOMA = CYLINDRICAL EPITHELIOMA
  • = Schneiderian PAPILLOMA
Incidence: 4% of all nasal neoplasms; most common of epithelial papillomas; commonly occurring after nasal surgery
Cause: unknown; association with human papillomavirus-11
Age: 40–60 years; M:F = 3–5:1
Path: vascular mass with prominent mucous cyst inclusions interspersed throughout epithelium
Histo: hyperplastic epithelium inverts into underlying stroma rather than in an exophytic direction; high intracellular glycogen content
♢ Squamous cell carcinoma coexistent in 5.5–27%!
Location: uniquely unilateral (bilateral in <5%)
  • most often arising from the lateral nasal wall with extension into ethmoid/maxillary sinuses, at junction of antrum + ethmoid sinuses
  • paranasal sinus (most frequently maxillary antrum)
  • nasal septum (5.5–18%)
  • • unilateral nasal obstruction, epistaxis, postnasal drip, recurrent sinusitis, sinus headache
  • • distinctive absence of allergic history
  • commonly involves antrum + ethmoid sinus
  • widening of infundibulum/outflow tract of antrum
  • destruction of medial antral wall/lamina papyracea of orbit, anterior cranial fossa (pressure necrosis) in up to 30%
  • septum may be bowed to opposite side (NO invasion)
  • homogeneous enhancement
  • MR:
    • may have intermediate to low intensity on T2WI (DDx: squamous cell carcinoma, olfactory neuroblastoma, melanoma, small cell carcinoma)
Cx: (1) cellular atypia/squamous cell carcinoma (10%)
(2) recurrence rate of 15–78%
Rx: complete surgical extirpation (lateral rhinotomy with en bloc excision of lateral nasal wall)
P.387

Juvenile Angiofibroma
  • = most common benign nasopharyngeal tumor, can grow to enormous size and locally invade vital structures
Incidence: 0.5% of all head and neck neoplasms
Age: teenagers (mean age of 15 years); almost exclusively in males
  • • recurrent + severe epistaxis (59%)
  • • nasal speech due to nasal obstruction (91%)
  • • facial deformity (less common)
    Location: nasopharynx/posterior nares
    Extension: posterolateral wall of nasal cavity; via pterygopalatine fossa into retroantral region/orbit/middle cranial fossa; laterally into infratemporal fossa
  • widening of pterygopalatine fossa (90%) with anterior bowing of posterior antral wall
  • invasion of sphenoid sinus (2/3) from tumor erosion through floor of sinus
  • widening of inferior + superior orbital fissures (spread into orbit via inferior orbital fissure + into middle cranial fossa via superior orbital fissure)
  • highly vascular nasopharyngeal mass (only enhances on CT scan immediately after bolus injection); supplied primarily by internal maxillary artery
  • MR:
    • intermediate signal intensity on T1WI with discrete punctate areas of hypointensity (secondary to highly vascular stroma)
NOTE: Biopsy contraindicated!
Labyrinthitis
Cause: viral infection (mumps, measles) > bacterial infection > syphilis, autoimmune, toxins
  • • sudden hearing loss, vertigo, tinnitus
  • MR:
    • faint diffuse enhancement of labyrinth on T1WI (HALLMARK)
Ramsay-Hunt syndrome = herpes zoster oticus
  • • mucosal vesicles of external auditory canal
  • intracanalicular 8th nerve enhancement
Tympanogenic Labyrinthitis
Cause: agent enters through oval/round window in middle ear infection
Meningogenic Labyrinthitis
Cause: agent propagates along IAC/cochlear aqueduct in meningitis
Location: often bilateral
Labyrinthitis Ossificans
  • = LABYRINTHITIS OBLITERANS = SCLEROSING LABYRINTHITIS = CALCIFIC/OSSIFYING cochleitis
Cause: suppurative infection (tympanogenic, meningogenic, hematogenic) in 90%, trauma, surgery, tumor, severe otosclerosis
Meningitis is the most likely etiology!
Pathophysiology: progressive fibrosis + ossification of granulation tissue within labyrinth
  • • bi -/ unilateral profound deafness
  • loss of normal fluid signal within labyrinth on T2WI (early in course of disease)
  • inner ear structures filled with bone
Laryngeal Carcinoma
Incidence: 98% of all malignant laryngeal tumors; in 2% sarcomas
Risk factors: smoking, alcohol abuse, airborne irritants
Histo: squamous cell carcinoma
Suggestive of lymph node metastasis:
  • lymph node >1.5 cm in cross section
  • proximity to laryngeal mass
  • cluster of >3 lymph nodes 6–15 mm in size
Supraglottic Carcinoma
Incidence: 20–30% of all laryngeal cancers
Metastases: early to lymph nodes of deep cervical chain, in 25–55% at time of presentation
  • • symptomatic late in course of disease (often T3/T4)
    Stage:
    T1 tumor confined to site of origin
    T2 involvement of adjacent supraglottic site/glottis without cord fixation
    T3 tumor limited to larynx with cord fixation or extension to postcricoid area/medial wall of pyriform sinus/preepiglottic space
    T4 extension beyond larynx with involvement of oropharynx (base of tongue)/soft tissue of neck/thyroid cartilage
  • ANTERIOR COMPARTMENT
    • Epiglottic carcinoma
      • circumferential relatively symmetric growth
      • extension into preepiglottic space ± base of tongue ± paraglottic space
        Prognosis: better than for tumors of posterolateral compartment
  • POSTEROLATERAL COMPARTMENT
    • Aryepiglottic fold (marginal supraglottic) carcinoma
      • exophytic growth from medial surface of aryepiglottic fold
      • growth into fixed portion of epiglottis + paraglottic (= paralaryngeal) space
    • False vocal cord/laryngeal ventricle carcinoma
      • submucosal spread into paraglottic space
      • ± destruction of thyroid cartilage
      • ± involvement of true vocal cords
      Prognosis: poorer than for cancer of the anterior compartment
Glottic Carcinoma
Incidence: 50–60% of all laryngeal cancers
  • • early detection due to hoarseness
Stage:
T1 tumor confined to vocal cord with normal mobility
T2 supra-/subglottic extension ± impaired mobility
T3 fixation of true vocal cord
T4 destruction of thyroid cartilage/extension outside larynx
P.388

Patterns of tumor invasion:
  • anterior extension into anterior commissure
    • >1 mm thickness of anterior commissure
    • invasion of contralateral vocal cord via anterior commissure
  • posterior extension to arytenoid cartilage, posterior commissure, cricoarytenoid joint
  • subglottic extension
    • tumor >5 mm inferior to level of vocal cords
  • deep lateral extension into paralaryngeal space
Prognosis: T1 carcinoma rarely metastasizes (0–2%) due to absence of lymphatics within true vocal cords
Subglottic Carcinoma
Incidence: 5% of all laryngeal cancers
  • • late detection due to minimal symptomatology
Stage:
T1 confined to subglottic area
T2 extension to vocal cords ± mobility
T3 tumor confined to larynx + cord fixation
T4 cartilage destruction/extension beyond larynx
Prognosis: poor due to early metastases to cervical lymph nodes (in 25% at presentation)
Laryngeal Chondrosarcoma
  • The most common sarcoma of the larynx
Age: 50–70 years; M >> F
  • • lobulated submucosal mass
Location: posterior lamina of cricoid cartilage (50–70%), thyroid cartilage (20–35%)
  • coarse/stippled intratumoral calcifications
  • ± locally invasive
  • MR:
    • very high signal intensity of tumor matrix on T2WI (corresponding to hyaline cartilage)
Rx: function-preserving laryngeal resection (local recurrence may be seen 10 years or more)
DDx: benign chondroma
Laryngeal Hemangioma
Histo: cavernous/capillary type
  • • dark bluish red/pale red compressible swelling on endoscopy
  • strong contrast enhancement
  • CT:
    • phleboliths (PATHOGNOMONIC for cavernous type)
  • MR:
    • very high signal intensity on T2WI
DDx: paraganglioma, hypervascular metastasis (renal adenocarcinoma)
Infantile Laryngeal Hemangioma (10%)
  • = SUBGLOTTIC HEMANGIOMA
  • Most common subglottic soft-tissue mass causing upper respiratory tract obstruction in neonates
Age: <6 months; M:F = 1:2
  • crouplike symptoms (dyspnea, stridor) in neonatal period
  • hemangiomas elsewhere (skin, mucosal membranes) in 50%
Location: subglottic region
  • eccentric thickening of subglottic portion of trachea (AP view)
  • arises from posterior wall below true cords (lateral view)
Rx: tracheostomy (waiting for spontaneous regression)
Adult Laryngeal hemangioma
Location: supraglottic region (isolated); associated with extensive cervicofacial angiodysplasia
M > F
Rx: laser excision, cryotherapy, selective embolization
Laryngeal Papillomatosis
  • = RECURRENT RESPIRATORY PAPILLOMATOSIS
  • Squamous papilloma is the most common benign tumor of the larynx!
Etiology: human papilloma virus types 6 + 11 (papova virus causing genital condyloma acuminatum)
Histo: core of vascular connective tissue covered by stratified squamous epithelium
Age of onset: 1–54 years; M:F = 1:1; bimodal distribution
  • <10 years (diffuse involvement) = juvenile laryngotracheal papillomatosis; probably caused by transmission from mother to child during vaginal delivery
  • 21–50 years (usually single papilloma)
  • • progressive hoarseness/aphonia
  • • repeated episodes of respiratory distress
  • • inspiratory stridor, asthmalike symptoms
  • • cough
  • • recurrent pneumonia
  • • hemoptysis
Location: a) uvula, palate
(b) vocal cord
(c) subglottic extension (50–70%)
(d) pulmonary involvement (1–6%)
  • thickened lumpy cords
  • bronchiectasis
Cx:
  • Tracheobronchial papillomatosis (2–5%)
    Cause: tracheostomy
    Location: lower lobe + posterior predilection
    • solid pulmonary nodules in mid + posterior lung fields
    • 2–3 cm large thin-walled cavity with 2–4 mm thick nodular wall (foci of squamous papillomas enlarge centrifugally, undergo central necrosis, cavitate)
    • peripheral atelectasis + obstructive pneumonitis
  • pulmonary papillomatosis
    • from aerial dissemination (bronchoscopy, laryngoscopy, tracheal intubation) 10 years after initial diagnosis
    • irregularities of tracheal/bronchial walls
    • noncalcified granulomata progressing to cavitation
  • Malignant transformation into invasive squamous cell carcinoma
Rx: CO2 laser resection/surgical excision
Laryngeal Plasmacytoma
Age: 50–70 years; M > F
Histo: large sheets of uniform cells indistinguishable from normal plasma cells; marked amyloid deposition (20%)
  • • pedunculated/slightly prominent mass that bleeds easily
Location: epiglottis, true + false vocal cords
P.389

CT:
  • large smoothly marginated homogeneous mass
  • no significant contrast enhancement
Laryngocele
= dilated appendix/sacculus of the laryngeal ventricle extending beyond the superior border of the thyroid cartilage
Incidence: 1:2,500,000
Age: middle-aged men
Anatomy: laryngeal ventricle of Morgagni is a slitlike cavity between true + false cords; along the anterior third of its roof arises the small blind mucosa-lined laryngeal saccule of Hilton/laryngeal appendix; it extends superiorly between false vocal cord and aryepiglottic fold medially + thyroid cartilage laterally; the laryngeal appendix is relatively large in infancy; usually involutes by 6th year of life
Pathogenesis: chronic increase in intraglottic pressure
Cause: excessive coughing, shouting, playing wind instrument, blowing glass, obstruction of appendicular ostium (= secondary laryngocele) by chronic granulomatous disease/laryngeal neoplasm (15%)
N.B.: Almost 50% of laryngoceles detected with plain radiography contain a laryngeal carcinoma!
Histo: lined by pseudostratified columnar ciliated epithelium + mixture of submucosal serous and mucous glands
Types:
  • internal (40%) = in parapharyngeal space confined within thyrohyoid membrane
  • external (26%) = protrusion through thyrohyoid membrane at the point of insertion of the neurovascular bundle (superior laryngeal nerve + vessels) presenting as lateral neck mass near hyoid bone with normal size inside the membrane
  • mixed (44%) = internal + external dilatation of saccule on both sides of thyrohyoid membrane
  • visible in 10% of adults during phonation
  • hoarseness/dysphagia/stridor (internal laryngocele)
  • compressible anterior neck mass just below angle of mandible (external laryngocele)
  • Bryce sign = gurgling/hissing sound on compression
Site: unilateral (80%), bilateral (23%)
  • sharply defined round/oval radiolucent area within paralaryngeal soft tissues:
    • increase in size during Valsalva maneuver
    • decrease in size during compression
  • cystic mass that can be followed to level of ventricle
  • may be filled with fluid/contain air-fluid level
  • DIAGNOSTIC = connection between air sac + airway
Cx: infection (laryngopyocele) in 8–10%, formation of mucocele
DDx: laryngeal cyst (lined by squamous epithelium); lateral pharyngeal diverticulum (fills with barium)
Laryngomalacia
  • = immaturity of cartilage; most common cause of stridor in neonate + young infant
  • • only cause of stridor to get worse at rest
  • hypercollapsible larynx during inspiration (supraglottic portion only)
  • backward bent of epiglottis + anterior kink of aryepiglottic folds during inspiration
Prognosis: transient (disappears by age 1 year)
Lingual Thyroid
= solid embryonic rest of thyroid tissue, which remains ectopic along the tract of thyroglossal duct
Incidence: in 10% of autopsies (within tongue <3 mm); M << F
  • may be only functioning thyroid tissue (70–80%)
  • asymptomatic (usually)
  • may enlarge causing dysphagia/dyspnea
Location: midline dorsum of tongue near foramen cecum (majority), thyroglossal duct, trachea
CT
  • small focus of intrinsic high attenuation
Cx: malignancy in 3% (papillary carcinoma)
Lymphangioma
= congenital lymphatic malformation
Incidence: 5.6% of all benign tumors of infancy + childhood
Age: present at birth in 50–65%, in 80–90% evident by age 2 (time of greatest lymphatic growth); M = F
Lymphatic development:
  • endothelial buds from veins in jugular region form confluent plexuses, which develop into rapidly enlarging bilateral juguloaxillary lymph sacs (7.5 weeks GA); these fused lymph sacs extend craniad and dorsolateral with extensive outgrowth of lymph vessels in all directions; connection with internal jugular vein at level of confluence with external jugular vein persists on the left side
Pathogenesis:
  • early sequestration of embryonic lymphatic tissue with failure to join central lymphatic channels
  • congenital obstruction of lymphatic drainage due to abnormal budding of lymph vessels (= loss of connection/noncommunication of primordial jugular lymphatic sac with jugular vein)
Classification (based on size of lymphatic spaces):
  • Cystic lymphangioma = cystic hygroma
  • Cavernous lymphangioma
    • = mildly dilated cavernous lymphatic spaces with cysts of intermediate size
    Location: tongue, floor of mouth, salivary glands
    • penetration of contiguous structures
    • same signal intensities as cystic lymphangioma + fibrous stromal component of low intensity on T1WI + T2WI
  • Capillary/simple lymphangioma (least common)
    • = capillary-sized lymphatic channels
    Location: epidermis + dermis of proximal limbs
  • Vasculolymphatic malformation
    • composed of lymphatic + vascular elements, eg, lymphangiohemangioma
Histo: endothelial-lined lymphatic channels containing serous/milky fluid + separated by connective tissue stroma
  • • asymptomatic (in majority) soft/semifirm mass
  • • ± dyspnea/dysphagia with encroachment upon trachea, pharynx, esophagus
  • P.390

  • • rapid increase in size (from infection/hemorrhage)
    Location: anywhere in developing lymphatic system; mostly in posterior cervical triangle, occasionally in floor of mouth/tongue
    (a) posterior triangle of neck (75%), with extension into mediastinum in 3–10%
        • visible at birth in 65%
        • clinically apparent by end of 2nd decade in 90%
    (b) anterior mediastinum (<1%)
    (c) axilla (20%), chest wall, groin
    (d) retroperitoneum, abdominal organs, bone
  • multilocular thin-walled cysts separated by fibrous tissue
  • well-marginated small lesions/ill-defined infiltrative large lesions
Cx: infection, airway compromise, chylothorax, chylopericardium
Prognosis: spontaneous regression (10–15%)
Rx: surgical excision (treatment of choice but difficult since mass does not follow tissue planes) with recurrence rate of up to 15%
Cystic Hygroma
  • = CYSTIC LYMPHANGIOMA
  • = single/multiloculated fluid-filled cavities on either side of fetal neck + head (localized form) ± trunk (generalized form) as the most common form of lymphangioma developing within loose connective tissue
Incidence: 1:6,000 pregnancies
Path: multiple enormously dilated cystic lymphatic channels; varying between a few mm to >10 cm in diameter containing chylous fluid; separated by minimal intervening stroma; may invade adjacent soft tissues/muscle and surround vessels
Histo: cystic spaces lined by endothelial cells + supporting connective tissue stroma
Associated with:
  • chromosomal abnormalities in 60–80% (in particular when detected in 2nd trimester)
    • Turner syndrome (45 XO, mosaic) in 40–80%
    • Trisomies 13, 18, 21, 13q, 18p, 22
    • Noonan syndrome
    • Distichiasis (= second row of hair behind eyelash) -lymphedema syndrome
    • Familial pterygium colli
    • Roberts, Cumming, Cowchock syndrome
    • Achondrogenesis type II
    • Lethal pterygium syndrome
  • exposure to teratogens
    • Fetal alcohol syndrome
    • aminopterin
    • trimethadione
Types:
  • Cystic hygroma with abnormal peripheral lymphatic system
    • lymphangioma in posterior compartment of neck
    • septations (indicate high probability for aneuploidy, development of hydrops, and perinatal death)
  • Diffuse lymphangiectasia
    • lymphangioma of chest + extremities
    • peripheral lymphedema + nonimmune hydrops
  • Isolated cystic hygroma
    • axillary lymph sac malformation
      • lymphangioma restricted to axilla
    • jugular lymph sac malformation
      • lymphangioma restricted to lateral neck
    • internal thoracic + paratracheal lymph sac malformation
      • lymphangioma within mediastinum
    • combined lymph sac malformation
    • thoracic duct malformation
      • thoracic duct cyst
  • • AF-AFP/MS-AFP may be elevated
Location: neck (frequently posterior cervical space) and lower portions of face (75–80%), mediastinum (3–10%, in 1/2 extension from neck), axilla (20%), chest wall (14%), face (10%), retroperitoneum (kidneys), abdominal viscera (colon, spleen, liver), groin, scrotum, skeleton
US:
  • thin-walled fluid-filled structure with multiple septa of variable thickness + solid cyst wall components
  • fluid-fluid level with layering hemorrhagic component
  • isolated nuchal cysts
  • webbed neck (= pterygium colli) following later communication with jugular veins
  • nonimmune hydrops (43%)
  • progressive peripheral edema
  • fetal ascites
  • oligo-/polyhydramnios/normal amount of fluid
  • bradycardia
CT:
  • poorly circumscribed multiloculated masses
  • homogeneous attenuation of fluid values/higher (after infection)
MR:
  • low signal intensity on T1WI
  • high signal intensity lesion with low-signal intensity septations of variable thickness on T2WI
  • may be hyperintense on T1WI (due to clotted blood/high chylous lipid content/high protein content)
  • ± fluid-fluid level (if hemorrhage present)
DDx: hemangioma (different location, feeding vessels, contrast enhancement)
Cx:
  1. Compression of airways/esophagus
  2. Slow growth/sudden enlargement (hemorrhage, inflammation)
Prognosis:
  • Intrauterine demise (33%)
  • Mortality of 100% with hydrops
  • Spontaneous regression (10–15%)
  • Favorable prognosis for localized lesions of anterior neck + axilla
  • Only 2–3% of fetuses with posterior cystic hygroma become healthy living children!
DDx: twin sac of blighted ovum, cervical meningocele, encephalocele, cystic teratoma, nuchal edema, branchial cleft cyst, vascular malformation, lipoma, abscess
P.391

Pseudocystic Hygroma
  • = PSEUDOMEMBRANE
  • = anechoic space bordered by specular reflection on posterior aspect of fetal neck during 1st trimester
Cause: ? developing integument
  • NO prominent posterior bulge/internal septations
Madelung Disease
  • = Benign Symmetrical Lipomatosis
  • = rare benign condition characterized by deposition of massive amounts of adipose tissue in neck, shoulders, upper chest
Cx: tracheal compression with respiratory compromise
Malignant External Otitis
= severe bacterial infection of the soft tissues + bones of base of skull
Organism: almost always Pseudomonas aeruginosa
Age: elderly
Predisposed: diabetes mellitus/immunocompromised
  • unrelenting otalgia, headache
  • purulent otorrhea unresponsive to topical antibiotics
  • may cause malfunction of nerves VII, IX, X, XI
Location: at bone-cartilage junction of EAC
Spread of infection: (a) inferiorly into soft tissues inferior to temporal bone, parotid space, nasopharyngeal masticator space
(b) posteriorly into mastoid
(c) anteriorly into temporomandibular joint
(d) medially into petrous apex
CT:
  • soft-tissue density in external auditory canal (100%)
  • fluid in mastoid/middle ear (89%)
  • disease around eustachian tube (64%)
  • obliteration of fat planes beneath temporal bone (64%)
  • involvement of parapharyngeal space (54%)
  • masticator space disease (27%)
  • mass effect in nasopharynx (54%)
  • bone erosion of clivus (9%)
  • intracranial extension (9%)
Cx: bone destruction, osteomyelitis, abscess
Prognosis: 20% recurrence rate
DDx: malignant neoplasm
Mucocele
= end stage of a chronically obstructed sinus
Incidence: most common lesion to cause expansion of paranasal sinus; increased incidence in cystic fibrosis
Etiology: obstructed paranasal sinus ostium
Path: expanded sinus cyst lined
Age: Usually abulthood
  • history of chronic nasal polyposis + pansinusitis
  • commonly present with unilateral proptosis
  • decreased visual acuity, visual field defect
  • palpable mass in superomedial aspect of orbit (frontal mucocele)
  • intractable headaches
Location:
mnemonic: fems
frontal (60%) > ethmoid (30%) > maxillary (10%) > sphenoid (rare)
  • soft-tissue density mass
  • sinus cavity expansion (DDx: never in sinusitis)
  • bone demineralization + remodeling at late stage but NO bone destruction (impossible DDx from neoplasm)
  • surrounding zone of bone sclerosis/calcification of edges of mucocele (from chronic infection)
  • macroscopic calcification in 5% (especially with superimposed fungal infection)
  • uniform enhancement of thin rim
US:
  • homogeneous hypoechoic mass
MR:
  • signal intensity varies with state of hydration, protein content, hemorrhage, air content, calcification, fibrosis
  • hypointense on T1WI + signal void on T2WI due to inspissated debris + fungus
  • peripheral enhancement pattern (DDx from solid enhancement pattern of neoplasms)
Cx: (1) protrusion into orbit displacing medial rectus muscle laterally
(2) expansion into subarachnoid space resulting in CSF leak
(3) mucopyocele = superimposed infection (rare)
DDx: paranasal sinus carcinoma, Aspergillus infection (enlargement of medial rectus muscle + optic nerve, focal/diffuse areas of increased attenuation), chronic infection, inverting papilloma
Mucoepidermoid Carcinoma
Path: arises from intercalated ducts of seromucinous glands
Histo: composed of a mixture of 3 cells: mucin-secreting cells + squamous cells + mucous cells; arranged in cords/sheets/cystic configuration
Prognosis: variable (well-encapsulated low-grade to infiltrating highly aggressive malignancy)
Rx: complete surgical removal
Parotid Mucoepidermoid Carcinoma
  • Most common malignant lesion of parotid gland
  • In children: up to 35% of all salivary gland tumors are malignant - 60% are mucoepidermoid carcinomas
  • • rock-hard mass
  • • pain/itching along course of facial nerve
  • • facial nerve paralysis
CT:
  • may contain cystic low-attenuating areas
  • focal calcifications (rare)
  • low-grade lesion
    • well-circumscribed parotid mass
    • hypo- to isointense on T1WI
    • hyperintense on T2WI
      Rx: wide local excision
  • high-grade lesion
    • infiltrating poorly marginated, more solid, relatively homogeneous lesion with few cystic areas
    Rx: wide block excision + radical neck dissection
P.392

Laryngeal Mucoepidermoid Carcinoma
Incidence: ∼ 100 cases
  • M:F = 6:1
Location: epiglottis (most common)
Nasal Glioma
  • misnomer (no neoplastic features) = NASAL CEREBRAL HETEROTOPIA
  • rare developmental mass composed of dysplastic sequestered neurogenic tissue that has become isolated from the subarachnoid space
Age: usually identified at birth
Location: extranasal (60%); intranasal (30%); combination of intra- and extranasal (10%)
Site: unilateral right > left side
  • • no change in size during crying
  • may parallel the rate of brain growth
  • attached to middle turbinate bone/nasal septum
  • soft-tissue mass of glabella
  • attached to brain by stalk (10–30%)
  • MR:
    • iso-/hypointense relative to gray matter on T1WI
    • hyperintense on T2WI
Otic Capsule Dysplasia
Cochlear Aplasia
= Michel aplasia = Michel anomaly = agenesis of osseous + membranous labyrinth (rare)
Cause: arrested development at 4 weeks GA
  • • total sensorineural hearing loss
  • region of otic capsule normally occupied by cochlea is replaced by dense labyrinthine + pneumatized bone
  • flat medial wall of middle ear (= undeveloped horizontal semicircular canal)
  • hypoplasia of internal auditory canal
  • dysplasia of vestibule = marked enlargement into region of lateral + superior semicircular canals
DDx: labyrinthitis obliterans (no loss of lateral convexity of medial wall of middle ear)
Single-cavity Cochlea
  • = saccular defect/cavity in otic capsule in the position normally occupied by cochlea without recognizable modiolus, osseous spiral lamina, interscalar septum
  • • profound hearing loss discovered in early childhood
May be associated with: recurrent bacterial meningitis, perilymphatic fistula of oval window
  • cystic cochlea (= developed basal turn, middle + apical turn occupy common nondeveloped space)
Insufficient Cochlear Turns
  • = normal basilar turn + varying degrees of hypoplasia of middle and apical turns
Mondini malformation
  • = absence of anterior 1 1/2 turns of cochlea often with preservation of the basilar turn
Cause: in utero insult at 7 weeks GA
Frequency: 2nd most common imaging finding in children with sensorineural hearing loss
  • • some high-frequency hearing preserved
  • • vertigo
  • • otorrhea, rhinorrhea, recurrent meningitis (perilymphatic fistula caused by absence/defect of stapes footplate)
  • absence of cochlear apex
May be associated with: deformity of vestibule
+ semicircular canals
+ vestibular aqueduct
Anomalies of Membranous Labyrinth
  • Scheibe dysplasia = abnormal cochlea + saccule
  • Alexander dysplasia = dysplasia of basal turn
  • normal CT findings
Small Internal Auditory Canal
  • = decrease in the diameter of IAC due to hypoplasia/aplasia of cochlear nerve (portion of cranial nerve VIII)
  • • total sensorineural hearing loss
  • hypoplastic anteroinferior quadrant of IAC
Large Vestibule
Associated with: underdeveloped lateral semicircular canal
  • • sensorineural hearing deficit (most common cause)
  • lateral semicircular canal smaller
  • vestibule extends further into lateral + superior aspects of otic capsule
Large Vestibular Aqueduct
= Enlarged vestibular aqueduct syndrome
Age: manifests around 3 years
Frequency: most common imaging abnormality detected in children with sensorineural hearing loss
  • unilateral congenital deafness (commonly missed)
  • vertigo, tinnitus (in 50%)
Location: bilateral in 50–66%
  • vestibular aqueduct >1.4–2 mm in diameter measured halfway between posterior petrous bone and common crus at level of vestibule
  • vestibular aqueduct larger than superior and posterior semicircular canals
Otosclerosis
  • = Otospongiosis
  • = replacement of dense otic capsule by highly vascular spongy bone in active phase (misnomer) with restoration of density during reparative sclerotic phase
Etiology: unknown; frequently hereditary
Age: adolescent/young adult Caucasian; M:F = 1:2
Histo: otosclerosis limited to endochondral layer
DDx: Paget disease, osteogenesis imperfecta, syphilis
Stapedial = Fenestral Otosclerosis (80–90%)
Location: anterior oval window margin (= fissula ante fenestrum); bilateral in 85%
  • • tinnitus early in course (2/3)
  • • progressive conductive hearing loss (stapes fixation in oval window)
  • oval window too wide (lytic phase)
  • P.393

  • new bone formation on anterior oval window margin ± posterior oval window margin ± round window
  • complete plugging of oval window = obliterative otosclerosis (in 2%)
Cochlear = Retrofenestral Otosclerosis (10–20%)
Invariably associated with: fenestral otosclerosis
  • • progressive sensorineural hearing loss (involvement of otic capsule/cytotoxic enzyme diffusion into fluid of membranous labyrinth)
  • • Schwartze sign = reddish hue behind tympanic membrane when promontory involved
  • “double ring/double lucent” = lucent halo around cochlea (may appear as 3rd turn to cochlea) in early phase
  • bony proliferation in reparative sclerotic phase difficult to diagnose because of same density as cochlea
Papillary Endolymphatic Sac Tumor
  • Heffner TUMOR
  • adenomatous tumor of the temporal bone
Origin: epithelial lining of endolymphatic sac
Associated with: von Hippel-Lindau disease (may have bilateral papillary endolymphatic sac neoplasms)
  • • hearing loss, facial nerve palsy, vestibular dysfunction
  • solid + cystic components
  • surrounded by thin shell of reactive bone
  • may be hypervascular (supplied by branches of external carotid artery)
  • intratumoral calcifications = “bone sequestra” from destruction of petrous bone
  • contrast enhancement
MR:
  • speckled pattern of hyperintensity on T1WI (mimicking glomus tumor)
  • may contain blood products (hyperintense on T1WI + hypointense on T2WI)
DDx: paraganglioma, cystic and papillary adenocarcinoma, chondroid lesions (benign chondroma, low-grade chondrosarcoma, chondromyxoid fibroma), cholesterol granuloma, metastatic disease
Paraganglioma
  • nonchromaffin PARAGANGLIOMA = GLOMUS TUMOR (describes the rich arborization of blood vessels and nerves)
    • = chemodectoma (reflective of the chemoreceptor tissue of origin) = GLOMERULOCYTOMA = ENDOTHELIOMA
    • = PERITHELIOMA = SYMPATHOBLASTOMA
    • = FIBROANGIOMA = SYMPATHETIC NEVI
  • rare neuroendocrine tumor arising from paraganglionic tissue found between base of skull and floor of pelvis; belong to amine-precursor-uptake decarboxylation (APUD) system characterized by cytoplasmic vesicles containing catecholamines
Paraganglion = collection of tissue of the extraadrenal neuroendocrine system, frequently located near nerves and vessels, with special chemoreceptor function
Origin: arises from nonchromaffin paraganglion cells of neuroectodermal origin; differs from adrenal medulla only in its nonchromaffin feature
Neuroendocrine system:
  • Adrenal paraganglioma arising from adrenal medulla = pheochromocytoma
  • Extraadrenal paraganglioma
    • Aorticosympathetic paraganglioma associated with sympathetic chain + retroperitoneal ganglia
    • Parasympathetic paraganglioma including branchiomeric chemodectoma, vagal + visceral autonomic paraganglioma
Glenner classification of extraadrenal paragangliomas:
  • Branchiomeric distribution
    • Associated with great vessels of chest + neck including carotid body, glomus jugulare, glomus tympanicum
  • Parasympathetic distribution
    • Associated with vagal nerve
    • Associated with aorticosympathetic chain in thoracolumbar region from aortic arch to urinary bladder, including organ of Zuckerkandl
    • Associated with visceral organs
Histo: acidophil-epithelioid cells in contact with endothelial cells of a vessel; storage of catecholamines (usually nonfunctioning); histologically similar to pheochromocytoma
Age: range of 6 months to 80 years; peak age in 5–6th decade; F:M = 4:1
Associated with: pheochromocytoma
  • tumor may secrete catecholamine (= functional paraganglioma); proportion of hormonally active tumors high for pheochromocytomas, intermediate for aorticosympathetic paragangliomas, low for parasympathetic paragangliomas
  • paroxysmal/permanent hypertension (due to secretion of vasopressor amines) with headache, pallor, perspiration, palpitations
  • pheochromocytomas secrete norepinephrine + epinephrine, extraadrenal paragangliomas secrete only norepinephrine, some paragangliomas produce dopamine
  • determination of free norepinephrine most sensitive with gas chromatography/high-pressure liquid chromatography (HPLC) performed on 24-hour urine specimens
Location of functioning paragangliomas:
  • adrenal medulla (>80%)
  • extraadrenal intraabdominal (8–16%)
  • extraadrenal in head & neck (2–4%)
    • Four primary sites in head & neck, chest:
      • Carotid body
      • Jugular foramen
      • Path of vagus nerve
      • Middle ear
    • Less common sites in head & neck:
      • sella turcica, pineal gland, cavernous sinus, larynx (laryngeal branches of vagus nerve), orbit (ciliary ganglion of the eye), thyroid gland, nasopharynx, mandible, soft palate, face, cheek
  • multiple paragangliomas in up to 20%, particularly in hereditary disorders (multiple endocrine neoplasia syndromes, neuroectodermal syndromes): Synchronous multicentricity in 3–26%:
    • autosomal dominant in 25–35%
    • nonhereditary in <5%
Cx: malignant transformation in 2–10%
P.394

Carotid Body Tumor
Embryology:
  • derived from mesoderm of 3rd branchial arch + neural crest ectoderm cells, which differentiate into sympathogonia (= forerunner of paraganglionic cells)
  • Chemodectoma is misnomer (not derived from chemoreceptor cells)!
Histo: nests of epithelioid cells (“Zellballen”) with granular eosinophilic cytoplasm separated by trabeculated vascularized connective tissue
  • Chromaffin-positive granules (= catecholamines) may be present
Function of carotid body:
  • 5 × 3 × 2 mm carotid body regulates pulmonary ventilation through afferent input by way of glossopharyngeal nerve to the medullary reticular formation
Chemoreceptor: detects changes in arterial partial pressures of O2 + CO2 + pH
Stimulus: hypoxia > hypercapnia > acidosis
Effect: increase in respiratory rate + tidal volume; increase in sympathetic tone (heart rate, blood pressure, vasoconstriction, elevated catecholamines)
  • painless pulsatile firm neck mass below the angle of the jaw, laterally mobile but vertically fixed
Location: within/outside adventitial layer of CCA at level of carotid bifurcation, commonly along posteromedial wall; bilateral in 5% with sporadic occurrence, in 32% with autosomal dominant transmission
  • enhancing oval mass with splaying of ICA + ECA above CCA bifurcation
  • no narrowing of ICA/ECA caliber
Extension: inferiorly to lower cranial nerves + pharynx; superiorly to skull base + intracranial cavity
Growth rate: about 5 mm/year
Cx: malignant transformation in 6% with metastases to regional lymph nodes, brachial plexus, cerebellum, lung, bone, pancreas, thyroid, kidney, breast
Glomus Tympanicum Tumor
Most common tumor in middle ear
  • hearing loss, pulsatile tinnitus
  • reddish purple mass behind tympanic membrane
Location: tympanic plexus on cochlear promontory of middle ear
  • CT (bone algorithm preferred):
    • globular soft-tissue mass abutting promontory
    • intense enhancement
    • usually small at presentation (early involvement of ossicles)
    • erosion + displacement of ossicles
    • inferior wall of middle ear cavity intact
  • Angio:
    • difficult to visualize because of small size
Glomus Jugulare Tumor
  • Most common tumor in jugular fossa with intracranial extension
  • Glomus jugulotympanicum tumor = large glomus jugulare tumor growing into the middle ear
Origin: adventitia of jugular vein
  • tinnitus, hearing loss
  • vascular tympanic membrane
Location: at dome of jugular bulb
  • soft-tissue mass in jugular bulb region/hypotympanum /middle ear space
  • intense enhancement
  • destruction of posteroinferior petrous pyramid + corticojugular spine of jugular foramen
  • destruction of ossicles (usually incus), otic capsule, posteromedial surface of petrous bone
  • MR:
    • “salt and pepper” appearance due to multiple small tumor vessels
  • Angio: (film entire neck for concurrent glomus tumors!)
    • hypervascular mass with persistent homogeneous reticular stain
    • invasion/occlusion of jugular bulb by thrombus/tumor
    • supplied by tympanic branch of ascending pharyngeal artery, meningeal branch of occipital artery, posterior auricular artery via stylomastoid branch, internal carotid artery, internal maxillary a.
    • arteriovenous shunting
Cx: malignant transformation with metastases to regional lymph nodes (in 2–4%)
Glomus Vagale Tumor
= PARAGANGLIA OF VAGUS NERVE = VAGAL BODY TUMOR
Histo: dispersed within perineurium/below nerve sheath/between nerve fiber fascicles; not organized into a compact mass
Location:
  • within inferior ganglion (= ganglion nodosum), inferior to base of skull close to jugular foramen (most common location)
  • within superior ganglion (= ganglion jugulare) within base of skull at level of jugular bulb
  • elsewhere along course of vagus nerve
Inferior Nodose Paraganglion
  • spindle-shaped mass
  • compression of internal jugular vein
  • displacement of carotid vessels anteromedially
  • displacement of lateral pharyngeal wall medially
  • minimal destruction of skull base
Superior Jugular Paraganglion
  • dumbbell-shaped mass
  • may encase/displace ICA
  • extension:
    • superiorly into posterior cranial fossa ± compression of brainstem
    • inferiorly into infratemporal/parapharyngeal space (2/3)
    • medially to involve arch of atlas
    • laterally into middle ear structures
    • posteriorly into mastoid air cells
  • Location in temporal bone:
    • dome of jugular bulb
    • mucosa of cochlear promontory related to tympanic branch of glossopharyngeal nerve (Jacobson nerve)
    • P.395

    • auricular branch of vagus nerve (Arnold nerve)
  • • slow growing + asymptomatic
  • spherical/ovoid/spindle-shaped mass with sharp interfacing margins and homogeneous enhancement
  • highly vascular mass + neovascularity + intense tumor blush
Cx: malignant transformation with metastases in 15% to regional lymph nodes + lung (other paragangliomas in 10%)
Paranasal Sinus Carcinoma
Location: maxillary sinus (80%), nasal cavity (10%), ethmoid sinus (5–6%), frontal + sphenoid sinus (rare)
Maxillary Sinus Carcinoma
Incidence: 80% of all paranasal sinus carcinomas
Histo: squamous cell carcinoma (80%)
Age: >40 years in 95%; M:F = 2:1
  • • asymmetry of face, tumor in oral/nasal cavity
  • bone destruction (in 90%) predominates over expansion
  • nodal metastases in 10–18%
Nasopharyngeal Carcinoma
Incidence: 10% of paranasal sinus carcinomas; 0.25–0.5% of all malignant tumors in whites; M>F
Predisposed: Chinese population
Histo: squamous cell carcinoma (>85%), nonkeratinizing ca., undifferentiated ca.
Mean age: 40 years
  • asymptomatic for a long time
  • history of chronic sinusitis/nasal polyps (15%)
  • unilateral nasal obstruction
Location: turbinates (50%) > septum > vestibule > posterior choanae > floor
Extension:
  • (a) lateral + superior: through sinus of Morgagni (= natural defect in superior portion of lateral nasopharyngeal wall) into cartilaginous portion of eustachian tube + levator veli palatini muscle
    • ± masticator space and pre- and poststyloid parapharyngeal spaces
    • ± involvement of levator + tensor veli palatini muscle, 3rd division of nerve V, petroclinoid fissure
    • ± foramen lacerum of skull base encasing internal carotid artery
    • ± cavernous sinus (along ICA/mandibular nerve/direct skull base invasion)
  • (b) anterior: posterior nasal cavity + pterygopalatine fossa
  • (c) inferior (1/3): submucosal spread along lateral pharyngeal wall + anterior and posterior tonsillar pillars
  • polypoid or papillary (2/3)
  • bone invasion (1/3)
  • MR:
    • signal intensity similar to that of adjacent mucosa
Ethmoid Sinus Carcinoma
Incidence: 5–6% of paranasal sinus carcinomas
Histo: squamous cell carcinoma (>90%), sarcoma, adenocarcinoma, adenoid cystic carcinoma; frequently secondarily involved from maxillary sinus carcinoma
  • nasal obstruction, bloody discharge
  • anosmia, broadening of nose
Parathyroid adenoma
Location: posterior to thyroid gland; ectopic in 5–15%
  • US (82% sensitive):
    • Often used after localization with Tc-99m MIBI scintigraphy
    • well-defined oval hypoechoic mass
    • multilobulated mass ± echogenic areas (in large adenoma)
  • CT:
    • Indication: ectopic mediastinal adenoma (detected in 50%)
  • MR:
    • hypointense on T1WI, hyperintense on T2WI + STIR NUC (Tc-99m MIBI):
    • increased radiotracer uptake
Parotid Hemangioma
Frequency: 90% of parotid gland tumors during 1st year of life; M < F
Histo: capillary type > cavernous type (in older children)
  • • soft-tissue mass developing shortly after birth with progressive growth peaking at age 1–2 years
  • • gradual spontaneous regression usually complete by adolescence
  • US:
    • hypoechoic mass relative to parotid tissue
    • variable degree of abnormal flow
  • CT:
    • occasionally phleboliths
    • well-defined mass with uniform intense enhancement
  • MR:
    • low to intermediate signal intensity on short TR
    • bright signal intensity on long TR
    • flow voids due to prominent vasculature
    Rx: surgery, sclerotherapy, laser ablation (therapy only with large size + encroachment on adjacent structures due to spontaneous regression)
Pharyngeal Abscess
Etiology: spread of infection from tonsils/pharynx
Age: children > adults
  • • trismus (most common presenting symptom) from involvement of pterygoid muscle
  • • sore throat
  • • low-grade fever
  • isodense/low-density mass with unsharp margins
  • rim enhancement
Cx: mycotic aneurysm of carotid artery (within 10 days)
Plasma Cell Granuloma
= rare benign pseudotumor
Cause: ?hypersensitivity
Histo: polyclonal infiltration of normal plasma cells mixed with other inflammatory cells + nonnecrotizing epithelial cell granulomas
Location: lung, GI tract, salivary glands, larynx
√ large homogeneous submucosal mass
DDx: multiple myeloma, solitary plasmacytoma
P.396

Pleomorphic Adenoma
= Benign Mixed Tumor Of parotis
mnemonic: 80% in parotid gland
80% in superficial lobe
80% benign
Incidence: 80% of all benign parotid tumors; 3rd most common tumor in pediatric parotid gland (after hemangioma + lymphangioma)
Histo: mixture of epithelial + myoepithelial cells
Age: usually >50 years
  • • slow-growing hard painless lump in cheek
  • round/oval/lobulated sharply marginated mass
  • rarely dystrophic calcifications
  • variable, usually mild contrast enhancement
  • US:
    • hypo- to isoechoic mass
    • ± hyperechogenic shadowing foci of calcifications
  • CT:
    • homogeneous well-defined tumor (if small)
    • less well-defined with low-density center if large (mucoid matrix, hemorrhage, necrosis)
  • MR:
    • hypointense on T1WI + hyperintense mass on T2WI
    • hyperintense areas in center (mucoid matrix)
Rx: facial nerve-sparing partial parotidectomy
Ranula
= mucus retention cyst due to obstruction of sublingual/adjacent minor salivary gland
  • (a) simple: confined to sublingual space
  • (b) diving: extends to below mylohyoid muscle into submandibular space
Ramsay-Hunt Syndrome
  • = Herpes Zoster Oticus
  • • vesicles in mucosa of external auditory canal
  • intracanalicular 8th nerve enhancement
Retropharyngeal Abscess/Hemorrhage
Etiology: upper respiratory tract infection, tonsillar infection, perforating injury of pharynx/esophagus, suppuration of infected lymph node
Organism: Staphylococcus, mixed flora
Age: usually <1 year
  • • fever, neck stiffness, dysphagia
  • thickness of retropharyngeal space >3/4 of AP diameter of vertebral body
  • reversal of cervical lordosis
  • anterior displacement of airway
  • may contain gas and gas-fluid level
Rhabdomyosarcoma
  • Frequency:
    • 5–10% of all malignant solid tumors in children <15 years of age (ranking 4th after CNS neoplasm, neuroblastoma, Wilms tumor); 3rd most common primary childhood malignancy of head + neck (following brain tumors + retinoblastomas); 10–25% of all sarcomas; annual incidence of 4.5:1,000,000 white + 1.3:1,000,000 black children
  • Most common soft-tissue tumor in children!
    Age: 2–5 years (peak prevalence); <10 years (70%); M:F = 2:1
  • Histo:
    • undifferentiated “blue cells” with scant cytoplasm + primitive-appearing nuclei; common perineural invasion
    • (a) embryonal rhabdomyosarcoma (>50%)
      subtype: polypoidal form = sarcoma botryoides = grapelike
    • (b) alveolar rhabdomyosarcoma (worst prognosis)
    • (c) pleomorphic rhabdomyosarcoma (mostly in adults)
  • • cranial nerve palsy
Location: head + neck (28–36%), trigone + bladder neck (18–21%), orbit (10%), extremities (18–23%), trunk (7–8%), retroperitoneum (6–7%), perineum + anus (2%), other sites (7%)
Site: paranasal sinus, middle ear, nasopharyngeal musculature (1/3) especially in masticator space; most common primary extracranial tumor invading the cranial vault in childhood
Metastases: lymph nodes (50%), lung, bone
  • bulky nasopharyngeal mass
  • extension into cranial vault through fissures + foramina (up to 35%) usually involving cavernous sinus
  • bone destruction by direct invasion
  • uniform enhancement
  • CT:
    • heterogeneous mass isodense to brain
    • expanded foramen/fissure
  • MR (imaging modality of choice):
    • signal intensity intermediate between muscle and fat on T1WI + hyperintense on T2WI
    • diffuse contrast enhancement
Prognosis: 12.5% 5-year survival
Rhinocerebral Mucormycosis
= paranasal sinus infection caused by nonseptated fungi Rhizopus arrhizus and Rhizopus oryzae
Spread: fungus first involves nasal cavity, then extends into maxillary/ethmoid sinuses/orbits/intracranially along ophthalmic artery/cribriform plate (frontal sinuses are spared)
  • Predisposed:
    • poorly controlled diabetes mellitus
    • chronic renal failure
    • cirrhosis
    • malnutrition
    • cancer
    • prolonged antibiotic therapy
    • steroid therapy
    • cytotoxic drug therapy
    • AIDS
    • extensive burns
  • • black crusting of nasal mucosa (in diabetics)
  • • small ischemic areas (invasion of arterioles + small arteries)
  • nodular thickening involving nasal septum + turbinates
  • mucoperiosteal thickening + clouding of ethmoids
  • focal areas of bone destruction
Cx:
  1. blindness
  2. cranial nerve palsy
  3. hemiparesis
Prognosis: high mortality rate
P.397

Sarcoidosis
Blacks: Whites = 10:1
Location: eye, lacrimal glands, salivary glands (30%), larynx (5%), involvement of intra- and extraparotid lymph nodes (rare)
  • granulomas may enhance
  • enlargement of optic canal (optic neuritis)
  • thickening of larynx with enhancement of granulomas
  • multiple small granulomas of septum + turbinates
  • NUC:
    • panda sign = Ga-67 uptake in both parotid glands + both lacrimal glands + nose
Heerfordt Syndrome
  • Parotid enlargement
    • May be the initial + only manifestation of sarcoid
    • • diffuse bilateral painless enlargement (10–30%)
    • • xerostomia
    • CT:
      • diffusely dense multiple noncavitating nodules within parotid gland/enlargement of intraparotid lymph nodes
  • Uveitis
  • Facial nerve paralysis
Uveoparotid Fever
  • Parotitis
  • Uveitis
  • Fever
Sialosis
= nontender noninflammatory recurrent enlargement of parotid gland
Cause: cirrhosis, alcoholism, diabetes, malnutrition, hormonal insufficiency (ovarian/pancreatic/thyroid), drugs (sulfisoxazole, phenylbutazone), radiation therapy
Histo: serous acinar hypertrophy + fatty replacement of gland
  • Sialography:
    • sparse peripheral ducts
  • CT:
    • enlarged/normal-sized gland
    • diffusely dense gland in end stage
Sinonasal Polyposis
= benign sinonasal mucosal lesion
Incidence: in 25% of patients with allergic rhinitis; in 15% of patients with asthma
Cause: allergic rhinitis (atopic hypersensitivity), asthma, cystic fibrosis (child), Kartagener syndrome, nickel exposure, nonneoplastic hyperplasia of inflamed mucous membranes
Location: commonly maxillary antrum
  • rounded masses within nasal cavity enlarging sinus ostium
  • expansion of sinus
  • thinning of bony trabeculae ± erosive changes at anterior skull base
  • usually peripheral/occasionally solid heterogeneous enhancement
DDx: cancer, fungal infection
Antrochoanal Polyp
= benign antral polyp, which widens the sinus ostium and extends into nasal cavity; 5% of all nasal polyps
Age: teenagers + young adults
  • antral clouding
  • ipsilateral nasal mass
  • smooth mass enlarging the sinus ostium
  • NO sinus expansion
Angiomatous polyp
= derivative of choanal polyp (following ischemia of polyp with secondary neovascularity along its surface)
DDx: juvenile angiofibroma (involvement of pterygopalatine fossa)
Sinusitis
  • Incidence:
    • most common paranasal sinus problem; most common chronic disease diagnosed in United States (31,000,000 people affected each year); complicating common colds in 0.5% (3–4 colds/year in adults, 6–8 colds/year in children)
  • Pathogenesis:
    • mucosal congestion as a result of viral infection leads to apposition of mucosal surfaces resulting in retention of secretions with bacterial superinfection
    • (1) Obstruction of major ostia
      • middle meatus draining frontal, maxillary, anterior ethmoid sinus
      • sphenoethmoidal recess draining posterior ethmoid sphenoid sinus
    • (2) Ineffective mucociliary clearing secondary to contact of two mucosal surfaces
  • Predisposing anatomic variants:
    • (1) greater degree of nasal septal deviation
    • (2) horizontally oriented uncinate process NOT concha bullosa, paradoxical turbinate, Haller cells, uncinate pneumatization
  • Location:
    • Infundibular pattern (26%)
      • = isolated obstruction of inferior infundibulum just above the maxillary sinus ostium
      • limited maxillary sinus disease
    • Ostiomeatal unit pattern (25%)
      • middle meatus opacification
    • Sphenoethmoidal recess obstruction (6%)
      • sphenoid/posterior ethmoid sinus inflammation
    • Sinonasal polyposis pattern
      • enlargement of ostia, thinning of adjacent bone
      • air-fluid levels
  • Plain films (Waters, Caldwell, lateral, submental vertex views):
    • acute sinusitis
      • air-fluid level [from retention of secretions secondary to mucosal swelling leading to ostial dysfunction] (54% sensitive, 92% specific in maxillary sinus)
      • total opacification
      • hyperintense secretions on T2WI (95% water content + 5% proteinaceous macromolecules)
    • Chronic sinusitis
      • mucosal swelling >5 mm thick on Waters view (99% sensitive, 46% specific in maxillary sinus)
      • P.398

      • bone remodeling + sclerosis (from osteitis)
      • polyposis
      • hyperattenuating lesion on NCCT (due to inspissated secretions/fungal disease)
      • hypointense secretions on T1WI + T2WI due to inspissated material with chronic obstruction (DDx: air)
  • CT:
    • to map bony anatomy for surgical planning
  • MR:
    • sinus thickening with high signal intensity on T2WI + low intensity on T1WI
    • near solid secretions with >28% protein concentration are hypointense on both T1WI + T2WI simulating air
    • rim gadolinium enhancement (DDx to neoplasms, which enhance centrally)
Cx:
  1. Mucous retention cyst (10%)
  2. Mucocele
  3. Orbital extension through neurovascular foramina, dehiscences, or thin bones: orbital cellulitis
  4. Septic thrombophlebitis
  5. Intracranial extension: meningitis, epidural abscess, subdural empyema, venous sinus thrombosis, cerebral abscess
Rx: functional endoscopic sinus surgery (amputation of uncinate process, enlargement of infundibulum + maxillary ostium, creation of common channel for anterior ethmoid air cells, complete/partial ethmoidectomy)
Allergic Sinusitis
Prevalence: 10% of population
  • • eosinophilic mucus (= pathological hallmark of allergic fungal sinusitis)
  • involves multiple sinuses
  • bilaterally symmetric
  • uniform enhancement
  • sinonasal polyposis
Bacterial Sinusitis
  • Organism:
    • acute phase: Streptococcus pneumoniae + Haemophilus influenzae (>50%), beta-hemolytic streptococcus, Moraxella catarrhalis
    • chronic phase: staphylococcus, streptococcus, corynebacteria, Bacteroides, fusobacteria
  • solitary antral disease (obstruction of sinus ostium)
  • uniform enhancement
Mycotic = Fungal Sinusitis
Organism: Aspergillus fumigatus, mucormycosis, bipolaris, Drechslera, Curvularia, Candida
  • polypoid lesion/fungus ball (= extramucosal infection due to saprophytic growth on retained secretions, usually caused by Aspergillus)
  • infiltrating fungal sinusitis (in immune-competent host)
  • fulminant fungal sinusitis (aggressive infection in immune-compromised individual/diabetics)
  • CT:
    • punctate calcifications (= calcium phosphate/calcium sulfonate deposition near mycelium)
  • MR:
    • dark on T2WI secondary to high fungal mycelial iron, magnesium, manganese content from amino acid metabolism (DDx: inspissated secretions/polypoid disease)
    Dx: failure to respond to antibiotic therapy
Sjögren Syndrome
  • = MYOEPITHELIAL SIALADENITIS
  • = autoimmune multisystem disorder (= collagen-vascular disease) characterized by inflammation + destruction of exocrine glands leading to dryness of mucous membranes affecting
    • salivary + lacrimal glands
    • mucosa + submucosa of pharynx
    • tracheobronchial tree
    • reticulo-endothelial system
    • joints
  • PRIMARY SJÖGREN SYNDROME
    • = autoimmune exocrinopathy
    • (a) recurrent parotitis in children
    • (b) SICCA SYNDROME = Mikulicz disease = xerophthalmia + xerostomia
  • SECONDARY SJÖGREN SYNDROME
    • Associated with:
      • connective tissue diseases
        • Rheumatoid arthritis (55%)
        • Systemic lupus erythematosus (2%)
        • Progressive systemic sclerosis (0.5%)
        • Psoriatic arthritis, primary biliary cirrhosis (0.5%)
      • lymphoproliferative disorders
        • Lymphocytic interstitial pneumonitis (LIP)
        • Pseudolymphoma (25%)
        • Lymphoma (5%; 44 × increased risk): mostly B-cell lymphoma
        • Waldenström macroglobulinemia
Age: 35–70 (mean 57) years; M:F = 1:9
Path: benign lymphoepithelioma
Histo: lymphocytic infiltrate associated ductal dilatation, acinar atrophy, interstitial fibrosis (= parotid destruction)
  • xerostomia (most common symptom) = atrophy of salivary + parotid glands leading to diminished saliva production and dryness of mouth + lips
  • xerophthalmia = dryness of eyes = keratoconjunctivitis sicca = desiccation of cornea + conjunctiva
  • xerorhinia = dryness of nose
  • decreased sweating
  • decreased vaginal secretions
  • swelling of parotid gland:
    • –recurrent acute episodes with tenderness; usually unilateral
    • –chronic glandular enlargement with superimposed acute attacks of painless progressive swelling
  • rheumatoid factor (positive in up to 95%)
  • ANA (positive in up to 80%)
  • mitochondrial antibodies (6%)
Location: lacrimal + salivary glands; mucous glands of conjunctivae, nasal cavity, pharynx, larynx, trachea, bronchi; extraglandular involvement in 5–10%
P.399

  • @ Chest
    • pulmonary fibrosis (10–14%, most common finding)
    • reticulonodular pattern (3–33–52%) involving lower lobes (= lymphocytic interstitial pneumonitis)
    • patchy consolidation
    • inspissated mucus
    • atelectasis
    • recurrent pneumonia
    • bilateral lower lobe bronchiectasis
    • acute focal/lipoid pneumonia (secondary to oils taken to combat dry mouth)
    • ± pleural effusion
    • HRCT:
      • bronchiectasis
      • bronchiolar inflammation
      • increased parenchymal lines
  • @ Parotid gland
    • Sialogram:
      • nonobstructive sialectasia (ducts + acini destroyed by lymphocytic infiltrates/infection)
        Stage I : punctate contrast collection <1 mm
        Stage II : globular contrast collection 1–2 mm
        Stage III : cavitary contrast collection >2 mm
        Stage IV : destruction of gland parenchyma
    • US:
      • enlarged heterogeneous gland with punctate areas of increased echogenicity (= mucus-filled ducts)
      • multiple scattered cysts bilaterally (= sialectasis = cystic dilatation of intraparotid ducts + glands)
      • increased vascularity on color Doppler
    • MR:
      • inhomogeneous “honeycomb”/“salt and pepper” appearance (= areas of low intensity between nodular parenchyma of high signal intensity) on T2WI/Gd-enhanced T1WI
Cx: Salivary gland lymphoma (occurs in significant number of patients + follows an aggressive course)
Subglottic Stenosis
  • CONGENITAL SUBGLOTTIC STENOSIS
    • • crouplike symptoms, often self-limiting disease
      Location: 1–2 cm below vocal cords
    • circumferential symmetrical narrowing of subglottic portion of trachea during inspiration
    • NO change in degree of narrowing with expiration
  • ACQUIRED SUBGLOTTIC STENOSIS
    • following prolonged endotracheal intubation (in 5%)
Thornwaldt CYST
  • = midline congenital pouch/cyst lined by ectoderm within nasopharyngeal mucosal space
Origin: persistent focal adhesion between notochord + ectoderm extending to the pharyngeal tubercle of the occipital bone
Incidence: 4% of autopsies
♢ Most common congenital head and neck cyst in child!
Peak age: 15–30 years
  • asymptomatic incidental finding
  • persistent nasopharyngeal drainage
  • halitosis
  • foul taste in mouth
Location: posterior roof of nasopharynx
  • smoothly marginated cystic mass of few mm to 3 cm in size
  • low density, not enhancing
  • NO bone erosion
Cx: infection of cyst
DDx: Rathke pouch (occurs in craniopharyngeal canal located anteriorly + cephalad to Thornwaldt cyst)
Thyroglossal Duct Cyst
Incidence: most common congenital neck mass (70% of all congenital neck anomalies); 2nd most common benign neck mass after benign lymphadenopathy
  • Embryogenesis:
    • thyroglossal duct = duct along which thyroid gland descends to its final position from foramen cecum at base of tongue (in 3rd week GA) passing anterior to hyoid bone; duct makes a recurrent loop through/posterior to precursor of hyoid bone before finally descending; inferior end becomes pyramidal lobe of thyroid; thyroid reaches final location by 7 weeks GA; duct usually involutes by 8–10th week of fetal life
Histo: cyst lined by stratified squamous epithelium/ciliated pseudostratified columnar epithelium ± mucous glands; ectopic thyroid tissue in 5–62%
Age: <10 years in 50%; 2nd peak at 20–30 years; M=F
  • enlarging painless midline neck mass
  • cyst moves upward with tongue protrusion
  • ± history of previous incision and drainage of an “abscess” in area of cyst
Location: suprahyoid (15%), at level of hyoid (20%), infrahyoid (65%)
Site: midline (75%), paramedian within 2 cm of midline frequently on left (25%)
Size: 1.5–3 cm (ranging from 0.5 to 6 cm)
  • midline cyst with occasional septation
  • infrahyoid cyst is embedded within strap muscle:
  • infrahyoid strap muscles beak over edge of cyst
  • US:
    • anechoic cyst (42%) in midline
    • hypoechoic mass with fine to coarse internal echoes (= proteinaceous material) + increased through transmission
  • Scintigraphy:
    • uptake in functional thyroid tissue of thyroglossal duct cyst
  • CT:
    • smooth well-circumscribed midline mass with thin wall
    • homogeneous attenuation of 10–18 HU/occasionally higher (due to increased protein content)
    • peripheral rim enhancement
    • tract of thyroid tissue between cystic mass + thyroid
  • MR:
    • cyst hypointense on T1WI + hyperintense on T2WI
    • nonenhancing rim (unless inflamed)
    • thick irregular rim + variable signal intensity of fluid with inflammation
Cx:
  1. infection
  2. thyroid carcinoma (1–4%): in 80% papillary ca.
  3. squamous cell carcinoma (even rarer)
Rx: Sistrunk procedure (= resection of central portion of hyoid bone + core of tissue following the expected course of entire thyroglossal duct) with a 2.6% recurrence rate
DDx:
  1. ectopic thyroid (no thyroid tissue in normal location)
  2. obstructed laryngocele (well-defined smooth mass in lateral aspect of superior paralaryngeal space connecting to larynx)
  3. branchial cleft cyst (round mass near mandibular angle displacing sternocleidomastoid muscle posterolaterally, carotid artery ± internal jugular vein posteromedially, submandibular gland anteriorly)
P.400

Thyroid Adenoma
  • round/oval mass of low attenuation with enhancement
Adenomatous Nodule (42–77%)
  • = COLLOID NODULE = ADENOMATOUS HYPERPLASIA = DEGENERATIVE INVOLUTED NODULE
Cytology: abundant colloid + benign follicular cells with uniform slightly large nuclei, arranged in a honeycomb pattern (difficult DDx from follicular tumors)
  • often multiple nodules by US/scintigraphy/surgery
  • mostly hypofunctioning, rarely hyperfunctioning
  • solid form = incompletely encapsulated, poorly demarcated nodules merging with surrounding tissue
  • cystic form (= colloid cyst) = anechoic areas in nodule (hemorrhage/colloid degeneration
  • calcific deposits
Follicular Adenoma (15–40%)
  • = monoclonal tumor arising from follicular epithelium
Path: single lesion with well-developed fibrous capsule
  • Histo subtypes:
    • Simple colloid (macrofollicular) adenoma:
      • most common form
    • Microfollicular (fetal) adenoma
    • Embryonal (trabecular) adenoma
    • Hörthle-cell (oxyphil/oncocytic) adenoma: large single polygonal cells with abundant granular cytoplasm + uniform eccentric nuclei + no colloid
    • Atypical adenoma
    • Adenoma with papillae
    • Signet-ring adenoma
    • 5% of microfollicular adenomas, 5% of Hörthle-cell adenomas, 25% of embryonal adenomas prove to be follicular cancers with careful study!
  • Functional status:
    • Toxic adenoma
    • Toxic multinodular goiter = hyperfunctioning adenoma within multinodular goiter; usually occurs in nodule >2.5 cm in size
    • Nonfunctioning adenoma
  • mass with increased/decreased echogenicity
  • “halo sign” = complete hypoechoic ring with regular border surrounding isoechoic solid mass
Thyroid Carcinoma
Incidence: 13,000 new cancers/year in United States; clinically silent cancers in up to 35% at autopsy/surgery (usually papillary carcinomas of <1.0 cm in size)
Age: <30 years; M > F
  • Types (in order of worsening prognosis):
    • papillary (50–80%) > follicular (10–20%) > medullary (6–10%) > anaplastic
  • • history of neck irradiation
  • • rapid growth
  • • stone-hard nodule
  • hypoechoic/hypoattenuating mass
  • irregular ill-defined border without halo
  • NO hemorrhage/liquefaction necrosis
  • ancillary findings:
    • lymphadenopathy
    • destruction of adjacent structures
    • loss of fat planes
    • distant metastasis
Radiation-induced Thyroid Cancer
  • Incidence increases with doses of thyroidal irradiation from 6.5–1,500 rad (higher doses are associated with hypothyroidism)
Peak occurrence: 5–30 (up to 50) years post irradiation
  • Thyroid abnormalities in 20%:
    • (a) in 14% adenomatous hyperplasia, follicular adenoma, colloid nodules, thyroiditis
    • (b) in 6% thyroid cancer
  • Nondetectable microscopic foci of cancer in 25% of patients operated on for benign disease!
  • In patients with multiple cold nodules frequency of cancer is 40%
Diagnostic Whole-body I-131 scintigram
Indication: to detect metastases of thyroid carcinoma after total thyroidectomy; preferred over bone scan (only detects 40%) for skeletal metastases
  • Metastases not detectable in presence of normal functioning thyroid tissue because uptake is much less in metastases
  • Tc-99m pertechnetate is useless because of high background activity + lack of organification
  • False-negative I-131 scan in 24% secondary to nonfunctioning metastases
  • Technique:
    • low iodine diet for 7 days = avoid iodized salt; milk and diary products; eggs; seafood; bread made with iodate dough conditioners; red food dyes; restaurant food; food containing iodized salt, sea salt, iodates, iodines, algin, alginates, agar agar
    • T4 replacement therapy discontinued for 6 weeks
    • short-acting T3 is administered for 4–6 weeks
    • T3 replacement therapy discontinued 10–14 days prior to whole-body scan
    • measurement of TSH level to confirm adequate elevation (TSH >30–50 mIU/mL; administration of exogenous TSH not desirable because of uneven stimulation)
    • oral administration of 0.6–5–10 mCi I-131
    • whole-body scan after 24–48–72 hours (low background activity)
  • N.B.: posttherapy scan (1 week after therapeutic dose) identifies more lesions than diagnostic scan
  • P.401

  • Normal sites of accumulation:
    • nasopharynx, salivary glands, stomach, colon, bladder, liver (I-131-labeled thryoxin produced by carcinoma metabolized in liver), breasts in lactating women (breast feeding must be terminated after administration of I-131)
  • CONTRAINDICATED during pregnancy!
Treatment for follicular/papillary Cancer
  • Surgery: total thyroidectomy + modified radical neck dissection
  • Postoperative radioiodine treatment with I-131 if diagnostic scan positive (multiple treatments are usually necessary)
    • Radioiodine therapy only appropriate for papillary/mixed/follicular thyroid carcinomas (NOT for medullary or anaplastic carcinomas)
    • ablation of thyroid tissue remnants
      Time interval: 6 weeks after surgery
      • • no thyroid hormone replacement for 3–4 weeks
      • Calculated dose:
        • = {(thyroid weight [g] × 80–120 μCi/g) π % uptake of I-123 by 24 hours} × 100
      • Estimated dose: 30–100 mCi I-131 orally
      • » rescan after 3–7 days:
        • no change from pre-ablation: on suppression therapy
        • new foci (in up to 16%): consider therapy
        • decreased uptake: may be due to “stunning”
    • Treatment of metastases
      • Middle-of-the-road dose:
        • » 100 mCi for residual neck activity
        • » 150 mCi for regional lymph node metastases
        • » 175 mCi for lung metastases
        • » 200 mCi for bone metastases
      • Tumor dose:
        • 150 mCi of I-131 with an uptake of 0.5% per gram of tumor tissue and a biologic half-life of 4 days will produce 25,000 rads to tumor
    • Rapid turnover rates may exist in some metastases (lower dose advisable)
    • Treatment of large tumors incomplete (range of beta radiation is a few mm)
    Cx: radiation thyroiditis, radiation parotitis, GI symptoms (nausea, diarrhea), minimal bone marrow depression, leukemia (2%), anaplastic transformation (uncommon), lung fibrosis (with extensive pulmonary metastases and dose >200 mCi)
  • Thyroid replacement therapy, exogenous thyroid hormone to suppress TSH stimulation of metastases
  • External radiation therapy for anaplastic carcinoma + metastases without iodine uptake
FOLLOW-UP: thyroglobulin >50 ng/mL indicates functioning metastases after complete ablation of thyroid tissue
Papillary Carcinoma of Thyroid (60–70%)
Peak age: 5th decade; F > M
Histo: unencapsulated well-differentiated tumor
  • purely papillary
  • mixed with follicular elements (more common, especially under age 40)
  • Metastases:
    • Lymphogenic spread to regional lymph nodes (40%, in children almost 90%)
    • Hematogenous spread to lung (4%), bone (rare)
  • • carcinoma elaborates thyroglobulin
  • NUC:
    • tumor usually concentrates radioiodine (even some purely papillary tumors)
  • US:
    • tumor of decreased echogenicity
    • purely solid/complex mass with areas of necrosis, hemorrhage, cystic degeneration
  • X-ray:
    • punctate/linear psammomatous calcifications at tumor periphery
Rx: lobectomy + isthmectomy for papillary cancer <1.5 to 2.0 cm in size isolated to one lobe
Prognosis: 90% 10-year survival for occult + intrathyroidal cancer; 60% 10-year survival for extrathyroidal cancer; worse prognosis with increasing age
Follicular Carcinoma of Thyroid (20%)
Peak age: 5th decade; F > M
Path: encapsulated well-differentiated tumor without papillary elements; in 25% multifocal
Histo: cytologically impossible to distinguish between well-differentiated follicular carcinoma + follicular adenoma (vascular invasion is the only criteria)
  • Early hematogenous spread to:
    • lung
    • bone (30%): almost always osteolytic (more frequent than in papillary carcinoma)
  • • carcinoma elaborates thyroglobulin
  • psammoma bodies + stromal calcium deposits
  • NUC:
    • usually concentrates pertechnetate, but fails to accumulate I-123
  • US:
    • indistinguishable from benign follicular adenoma
Prognosis: slow growing; 90% 10-year survival with slight/equivocal angioinvasion; 35% 10-year survival with moderate/marked angioinvasion
Anaplastic Carcinoma of Thyroid (4–15%)
Age: 6th–7th decade; M:F = 1:1
  • intrathoracic extension in up to 50%
  • ± invasion of carotid a., internal jugular v., larynx
  • NUC:
    • NO radioiodine uptake
  • CT:
    • mass with inhomogeneous attenuation
    • areas of necrosis (74%)
    • calcifications (58%)
    • regional lymphadenopathy (74%)
Prognosis: 5% 5-year survival; average survival time of 6–12 months
Medullary Carcinoma of Thyroid (1–5–10%)
sporadic/familial
P.402

Histo: arises from parafollicular C-cells, associated with amyloid deposition in primary + metastatic sites
Mean age: 60 years for sporadic variety;
during adolescence in MEN 2
  • May be associated with:
    • MEN 2a = pheochromocytoma + parathyroid hyperplasia (Sipple syndrome)
    • MEN 2b = without parathyroid component
Metastases: early spread to lymph nodes (50%), lung, liver, bone
  • • elevated calcitonin (from tumor production) stimulated by pentagastrin + calcium infusion
  • mass of 2–26 mm
  • granular calcifications within fibrous stroma/amyloid masses (50%)
  • local invasion (common)
  • nodal spread to neck + mediastinum (in up to 50%)
  • distant metastases to liver, lung, bone (15–25%)
  • NUC:
    • NO uptake by radioiodine/pertechnetate
    • frequently shows increased uptake of Tl-201
    • concentrates I-123 MIBG, pentavalent Tc-99m DMSA, In-111 octreotide
  • CT:
    • mass of low attenuation (no iodine concentration)
  • Prognosis:
    • 90% 10-year survival without nodal metastases
    • 42% 10-year survival with nodal metastases
Rx: total thyroidectomy + modified radical neck dissection
Thyroiditis
Hashimoto Thyroiditis
  • = CHRONIC LYMPHOCYTIC THYROIDITIS
  • Most frequent cause of goitrous hypothyroidism in adults in the USA (iodine deficiency is the more common cause worldwide)
Etiology: autoimmune process with marked familial predisposition; antibodies are typically present; functional organification defect
Peak age: 4th–5th decade; M > F
  • • firm rubbery lobular goiter
  • • gradual painless enlargement
  • • thyrotoxicosis in early stage (4%)
  • • decreased thyroid reserve
  • • hypothyroidism at presentation (20%)
  • moderate enlargement of both lobes (18%)
  • NUC:
    • low tracer uptake (occasionally increased) with poor visualization (4%)
    • prominent pyramidal lobe
    • positive perchlorate washout test
    • patchy tracer distribution
    • multiple (40%)/single cold defects (28%)/normal thyroid (8%)
  • US:
    • initially heterogeneous diffusely decreased echogenicity + slight lobulation of contour
    • marked hyperemia on color Doppler
    • later densely echogenic (fibrosis) + acoustical shadows
Cx: hypothyroidism
DeQuervain Thyroiditis
= SUBACUTE THYROIDITIS
Etiology: probably viral
Histo: lymphocytic infiltration + granulomas + foreign body giant cells
Peak age: 2nd–5th decade; M:F = 1:5
  • • upper respiratory tract infection precedes onset of symptoms by 2–3 weeks
  • • painful tender gland + fever; only mild enlargement
  • • hyperthyroidism (50%) secondary to severe destruction
  • • short-lived hypothyroidism (25%) secondary to hormone depletion of gland
  • NUC:
    • abnormally low radioiodine uptake with clinical and laboratory evidence of hyperthyroidism
    • poor visualization of thyroid (initially)
    • single/multiple hypofunctional areas (occasionally)
    • increased uptake during phase of hypothyroidism (late event)
Cx: permanent hypothyroidism (rare)
Prognosis: usually full recovery
Painless Thyroiditis
Histo: resembles chronic lymphocytic thyroiditis
  • clinical presentation similar to subacute thyroiditis
  • NOT painful/tender
Acute Suppurative Thyroiditis
US:
  • focal/diffuse enlargement; possibly abscess
  • decreased echogenicity
Toxic Autonomous Nodule
  • Plummer disease = Toxic adenoma
  • hyperthyroidism caused by one/two hyperfunctioning nodules independent of normal pituitary-thyroid control mechanism
  • All toxic autonomous nodules are autonomous; however, not all autonomous nodules are toxic
Cause: gene mutation of TSH receptors of adenoma surface (not autoimmunity) result in continuous activation
Histo: adenoma
  • • excessive serum levels of thyroid hormone
  • • suppressed TSH production
  • • clinically hyperthyroid
  • radioiodine uptake (RAIU) mildly to moderately elevated
  • concentration of radiopharmaceutical to a far greater degree than surrounding extranodular thyroid tissue
DDx: Graves disease (RAIU significantly elevated)
Toxic Multinodular Goiter
= multinodular goiter associated with hyperthyroidism
Cause: several of nodules have gradually formed areas of hyperplasia that eventually grew into autonomously functioning nodules
Age: elderly
  • • mildly elevated thyroid levels
  • P.403

  • • suppressed TSH
  • RAIU normal/slightly elevated
  • multiple “hot” nodules in the thyroid within suppressed extranodular thyroid tissue
DDx: Graves disease (younger patient, milder degree of thyrotoxicosis)
Warthin Tumor
= PAPILLARY CYSTADENOMA LYMPHOMATOSUM = ADENOLYMPHOMA
Incidence: 2nd most common benign tumor of parotid gland; bilateral in 10%
Age: about 50 years; M > F
Origin: from heterotopic salivary gland tissue within parotid lymph nodes (direct result of incorporation of lymphatic elements + heterotopic salivary gland ductal epithelium within intraparotid + periparotid nodes during embryonic development
Histo: CHARACTERISTIC double layer of oncocytes (= epithelial cells) resting on a dense lymphoid stroma
  • slow-growing painless mass
Location: often in tail of parotid gland
  • well-circumscribed single/multiple cystic/solid lesion in parotid region usually 3–4 cm in size
    • Most common lesion to manifest as unilateral + multifocal masses
    • Most common salivary neoplasm to manifest as multiple masses in one/both parotid glands
  • MR:
    • hypointense compared with fat/surrounding parotid tissue on T2WI
  • NUC:
    • increased uptake with Tc-99m, Tl-201, FDG
DDx: lymphoma, inflammatory disease
Rx: surgical resection