Middle ear, inner ear and temporal bone tumors - benign / nonneoplastic
Acoustic neuroma

Author: Nat Pernick, M.D. (see Authors page)

Revised: 23 February 2018, last major update October 2013

Copyright: (c) 2002-2018, PathologyOutlines.com, Inc.

PubMed Search: Acoustic neuroma [title] ear pathology

Cite this page: Pernick, N. Acoustic neuroma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/earacousticneuroma.html. Accessed March 20th, 2018.
Definition / general
  • Common terminology but inaccurate because does not derive from acoustic branch of CN VIII and is not a neuroma
  • Also called vestibular schwannoma, neurilemmoma, benign peripheral nerve sheath tumor
  • Benign (rarely malignant if associated with neurofibromatosis) neoplasm originating from Schwann cells of cranial nerve VIII, superior or vestibular branch
  • 10% of intracranial neoplasms, 90% of tumors at cerebellopontine angle
  • Usually women, more common in age 30s to 60s but wide age range
  • Sensorineural hearing loss, tinnitus, loss of equilibrium; may eventually compress adjacent cranial nerves (V, VII, IX, X, XI), cerebellum, brainstem
  • 8% are bilateral (associated with neurofibromatosis type 2)
  • 16% have symptoms of neurofibromatosis; these patients develop tumors as teenagers
Radiology description
  • Flaring, widening or erosion of internal auditory canal
Case reports
Gross description
  • Circumscribed, tan-white-yellow, rubbery / firm, up to 5 cm, variable cystic change
Gross images

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Tumor in cerebellopontine angle

Microscopic (histologic) description
  • Unencapsulated but otherwise resembles schwannomas at other locations
  • Interlacing fascicles of cells with indistinct cytoplasmic borders, elongated and twisted nuclei
  • Biphasic with Antoni A (cellular) and B (hypocellular, myxoid) patterns and Verocay bodies (whorling or palisading of nuclei)
  • Hyalinization of vessels
  • Commonly have regressive ("ancient") changes (cellular pleomorphism with hyperchromasia, cystic degeneration, necrosis, calcification, hemorrhage)
  • May be highly cellular (cellular schwannoma)
  • No / rare mitotic figures
  • Cystic change may be due to intratumoral hemorrhage (J Neurosurg 2006;105:576)
Positive stains
  • S100 (diffuse, strong)