Ear
Middle ear and inner ear tumors - benign / nonneoplastic
Vestibular schwannoma
Author: Nat Pernick, M.D.
Last author update: 1 October 2013
Last staff update: 15 December 2020
Copyright: 2002-2024, PathologyOutlines.com, Inc.
PubMed Search: Vestibular schwannoma ear pathology
Table of Contents
Definition / general | Symptoms | Radiology description | Case reports | Treatment | Gross description | Microscopic (histologic) description | Positive stains | Negative stains | Additional referencesCite this page: Pernick N. Vestibular schwannoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/earvestibularschwannoma.html. Accessed April 16th, 2024.
Definition / general
- "Acoustic neuroma" is inaccurate because does not derive from acoustic branch of CN VIII and is not a neuroma
- Also called 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
Symptoms
- 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
- 55 year old woman with Jacobson nerve schwannoma presenting as middle ear mass (AJNR Am J Neuroradiol 2000;21:1331)
- Patient with schwannoma of tympanic membrane (J Laryngol Otol 2006;120:247)
Treatment
- Complete excision, although often slow growing and may not need surgery (Skull Base 2006;16:95)
Gross description
- Circumscribed, tan-white-yellow, rubbery / firm, up to 5 cm, variable cystic change
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)
Negative stains
