Ears and Neck Pathology

Ears and Neck Pathology

Ears: General Information

• Disorders of the ears rarely shorten life
• Disorders of the ears often impact quality of life

Ears: Common Disorders

• Acute and Chronic Otitis
• Symptomatic otosclerosis
• Aural Polyps
• Labyrinthitis
• Carcinomas of the Large Ear
• Paragangliomas

Otitis Media

• Primarily affects infants and children
• Can manifest as serous exudate (viral) or suppurative (bacterial)
• Common bacterial causes include Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis
• Repeated acute episodes can lead to chronic disease
• Chronic cases are often caused by Pseudomonas aeruginosa, Staphylococcus aureus, fungus, or polymicrobial infections
• Chronic infection can perforate the eardrum, encroach on ossicles/labyrinth, spread to mastoid, and lead to vault/temporal cerebritis or abscess
• P. aeruginosa otitis media in individuals with diabetes is aggressive and destructive, causing necrotizing otitis media

Cholesteatomas

• Typically associated with chronic otitis media
• Cystic, non-neoplastic lesions (1-4 cm) lined by keratinizing squamous or metaplastic mucus-secreting epithelium
• Filled with amorphous debris and cholesterol spicules
• Chronic inflammation and eardrum perforation allows squamous epithelium ingrowth or metaplasia, forming squamous cell nests/cystic lesions
• Cyst rupture triggers inflammatory reaction with giant cells engulfing necrotic cells
• Progressive enlargement can erode ossicles, labyrinth, adjacent bone/tissue, and may produce visible neck masses

Otosclerosis

• Abnormal bone deposition in middle ear, specific oval window rim where stapes footplate sits
• Fibrous ankylosis of footplate often occurs early in life, bony overgrowth anchors footplate
• Degree of immobilization corresponds to the extent of hearing loss
• Most cases are familial and autosomal dominant
• Begins with bone resorption, then fibrosis and vascularization in oval window, replaced by dense new bone anchoring the stapes
• Process is slowly progressive and can lead to hearing loss

Tumors of the Ear

• Tumors of the external ear (pinna) are often basal cell or squamous cell carcinomas
• These tumors are more common in elderly men, and associated with actinic radiation
• Tumors within the canal are often squamous cell carcinoma, and more common in middle-aged to elderly women
• Tumors within the canal are not associated with sun exposure

Neck: Branchial Cyst

• Benign cysts found on the anterolateral neck aspect along the SCM muscle
• Thought to arise from remnants of the 2nd branchial arch
• Common in young adults, age 20-40
• Lined by stratified squamous or pseudostratified columnar epithelium, featuring lymphoid tissue with germinal centers
• Cyst contents may be clear and watery or mucinous
• Contents may contain desquamated cells and granular debris
• Cysts enlarge slowly; excision is an effective treatment
• Similar lesions may appear in/beneath the parotid gland or the tongue
• Most cystic SCCs in this region represent metastases from upper airway or digestive tract cancers

Neck: Thyroglossal Tract Cyst

• Remnant of the thyroid developmental tract
• Thyroid anlage begins near foramen cecum at the tongue base
• Cysts are lined with stratified squamous (near tongue base) or pseudostratified columnar epithelium (lower)
• Fibrous cyst wall may include lymphoid aggregates or thyroid remnants
• Treatment is surgical excision

Neck: Paraganglioma

• Paraganglia are neuroendocrine cell clusters linked to sympathetic and parasympathetic nervous systems
• Most common site for tumors is the adrenal medulla, resulting in pheochromocytomas
• ~70% of extra-adrenal paragangliomas occur in the head and neck region
• Can develop in 2 general locations:
  • Paravertebral: Have sympathetic connections and are chromaffin-positive (detects catecholamines)
    • Examples include the organ of Zuckerand1 and (rarely) the bladder
  • Great vessels: Innervated by parasympathetic nervous system; infrequently release catecholamines
    • Includes carotid/aortic bodies, jugulotympanic ganglia, vagus nerve ganglion nodosum, and clusters near oral cavity, nose, nasopharynx, larynx, and orbit
• A prototype of a parasympathetic paraganglioma
• Arises close to or bifurcation of the common carotid artery
• Round-to-oval chief cells surrounded by vascular septae (zellballen)
• Chief cells (neuroectodermal origin) stain strongly for neuroendocrine markers, including chromogranin, synaptophysin, neuron-specific enolase, CD56, and CD57
• Consist of tumor cells with abundant, clear or granular, eosinophilic cytoplasm and uniform, round to ovoid, vesicular nuclei
• Stromal network includes spindle-shaped sustentacular cells (positive for S-100 protein)
• Typically slow-growing and painless, manifesting in the 5th-6th decade
• Frequently recurs after incomplete resection
• Despite benign appearance, many metastasize to regional lymph nodes and distant sites
• Succinate dehydrogenase B (SDHB) mutations are associated with the highest rates of metastasis (30-50%)
• Histological features (mitoses, pleomorphism, vascular invasion) are not reliable predictors of clinical course