Ear
Middle ear, inner ear and temporal bone tumors - benign / non-neoplastic
Middle ear adenoma

Reviewer: Nat Pernick, M.D. (see Reviewers page)
Revised: 18 January 2015, last major update December 2006
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PubMed Search: Middle ear adenoma
Cite this page: Middle ear adenoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/earmiddleearadenoma.html. Accessed December 3rd, 2016.
Definition / General
  • Rare, benign glandular neoplasm originating from middle ear mucosa
  • First described in 1976 (Laryngoscope 1976;86:1123, Clin Otolaryngol Allied Sci 1976;1:17)
  • Neuroendocrine and epithelial differentiation; also called carcinoid tumor or amphicrine tumor (Ultrastruct Pathol 2001;25:73)
  • Rosai believes they form a continuum with carcinoid tumor and could be considered adenocarcinoid tumors
  • No gender preference, usually 20's to 40's, but wide age range
  • Affects all sites in middle ear
  • Occasionally perforates tympanic membrane and extends into external auditory canal
  • Not associated with chronic otitis media or cholesteatoma
  • Excellent prognosis; rarely is locally aggressive, invades vital structures, has regional metastases (Laryngoscope 2005;115:1660) or causes death
Case Reports
Treatment
  • Complete surgical excision
  • Mastoidectomy may be necessary for large lesions
  • Recurs with inadequate excision
Gross Description
  • Gray-white to red-brown, firm/rubbery masses
  • Relatively well circumscribed
  • Not encapsulated
  • No hemorrhage, mean 0.8 cm
Micro Description
  • Variable patterns (sheets, solid, trabecular, cystic, cribriform, glandular, NOT papillary) of glands or tubules composed of uniform single layer of cuboidal or columnar cells with variable eosinophilic cytoplasm and round/oval hyperchromatic nuclei, eccentric nucleoli (if present)
  • May appear plasmacytoid, may have significant pleomorphism
  • May produce PAS+ mucin
  • Sparse fibrous or myxoid stroma
  • No/rare mitotic figures, no necrosis
  • May have neuroendocrine differentiation morphologically and immunohistochemically
Micro Images

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Case of the Week #376:


Chromogranin

Synaptophysin

Cytokeratin AE1/3




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Trabecular growth pattern, salt and pepper chromatin

Trabeculae and ribbons

Glandular pattern

Glandular lumen

Prominent glandular pattern

Various patterns

Multiple patterns in single tumor

Pagetoid tumor spread

Carcinoid-type pattern

Fig 1-mucin; 2-CAM5.2+; 3-synaptophysin+

Positive Stains
  • Keratin (90%), CK7 (90%), chromogranin (88%), CAM5.2 (81%), mucin (intraluminal), lysozyme, neuron specific enolase (50%), synaptophysin (31%), serotonin (25%), S100 (15%), CK20 (6%, focal)
Negative Stains
  • Actin
Electron Microscopy Description
Electron Microscopy Images

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Neurosecretory granules

Differential Diagnosis