title: Rapidly progressive epithelioid malignant peripheral nerve sheath tumor of the vestibular nerve.
abstract: OBJECTIVE
  Spontaneous malignant peripheral nerve sheath tumors (MPNSTs) arising from the vestibular nerve are extremely rare. In this report, we detail the case of one such tumor including the first report of its response to radiosurgery.
  
  
  METHODS
  A 73-year-old woman presented with subacute sensorineural hearing loss, retroauricular pain, and facial nerve palsy.
  
  
  METHODS
  Magnetic resonance imaging (MRI) was obtained demonstrating findings suggestive of a vestibular schwannoma. The patient elected for gamma knife radiosurgery and 13 gray were administered to the lesion. Repeat MRIs showed that the mass quickly regressed after radiosurgery but recurred by 5 months. Subsequent microsurgical resection revealed an aggressive epithelioid MPNST of the vestibular nerve.
  
  
  METHODS
  Interval MRI results, histopathology, and immunohistochemistry.
  
  
  RESULTS
  We present radiographic and histopathologic confirmation of the malignant nature of this extremely rare lesion. We also document its rapid response after radiosurgery as further indication of the malignant nature of this lesion.
  
  
  CONCLUSIONS
  Early and complete resection of internal auditory canal masses with atypical clinical courses suggestive of malignancy is the best initial option to treat these tumors with the understanding that further treatment with radiation or chemotherapy is essential.
authors.affiliation: *Yale School of Medicine, †Department of Surgery, Section of Otolaryngology, and ‡Department of Neurosurgery, Yale School of Medicine, New Haven, Connecticut; §Division of Neurosurgery, Duke University Medical Center, Durham, North Carolina; and ∥Department of Pathology, Yale School of Medicine, New Haven, Connecticut, U.S.A.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Kuzmik
authors.forename: Elias M
authors.initials: EM
authors.lastname: Michaelides
authors.forename: Veronica L
authors.initials: VL
authors.lastname: Chiang
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Nonaka
authors.forename: Takanori
authors.initials: T
authors.lastname: Fukushima
authors.forename: Alexander O
authors.initials: AO
authors.lastname: Vortmeyer
authors.forename: Ketan R
authors.initials: KR
authors.lastname: Bulsara
mesh_terms: D000368:Aged; D003390:Cranial Nerve Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000601:surgery; D009442:Neurilemmoma / Q000473:pathology* / Q000601:surgery; D016634:Radiosurgery; D016896:Treatment Outcome; D014725:Vestibular Nerve / Q000473:pathology* / Q000601:surgery; D000160:Vestibulocochlear Nerve Diseases / Q000473:pathology* / Q000601:surgery