title: Rare Lesions of the Internal Auditory Canal.
abstract: Approximately 95% of tumors occurring within the internal auditory canal (IAC) are vestibular schwannomas. Many undergo stereotactic radiation without definitive tissue diagnosis. Rare IAC tumors are not all radiosensitive and are poorly described.
  
  
  
  Between 1992 and 2015, 289 consecutive patients with IAC lesions operated on were reviewed retrospectively.
  
  
  
  Fifteen patients (5.2%) (16 operations) had unusual histologic findings, including nonvestibular schwannomas (2 facial schwannomas, 2 cochlear schwannomas, 2 intermedius schwannomas), 3 meningiomas, 3 cavernous hemangiomas, a mucosa-associated lymphoid tissue lymphoma, an arachnoid cyst, and a lipochoristoma. None of these rare tumors could be identified before surgery. Three operative approaches were used: the retrosigmoid approach, middle fossa subtemporal approach, or translabyrinthine approach. Few complications occurred, including facial nerve palsy, loss of hearing, and vestibular function. Five-year average follow-up revealed one patient with recurrence.
  
  
  
  Clinical examination and imaging alone were insufficient to correctly identify these tumors. Definitive pathologicdiagnosis should be strongly considered to help tailor treatment.
authors.affiliation: Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, USA; Department of Neurosurgery, Hôpital Lariboisirère, Paris VII-Diderot University, Paris, France.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Mary In-Ping Huang
authors.initials: MIH
authors.lastname: Cobb
authors.affiliation: Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Ali R
authors.initials: AR
authors.lastname: Zomorodi
authors.affiliation: Department of Surgery, Division of Head and Neck Surgery & Communication Sciences, Duke University Medical Center, Duke Otolaryngology of Raleigh, Raleigh, North Carolina, USA.
authors.forename: Calhoun D
authors.initials: CD
authors.lastname: Cunningham
authors.affiliation: Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, USA; Department of Neurosurgery, Fukushima Takanori Skull Base Center, Shinyurigaoka General Hospital, Kanagawa, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Nonaka
authors.affiliation: Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, USA; Department of Neurosurgery, Southern TOHOKU General Hospital, Koriyama, Fukushima, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Satoh
authors.affiliation: Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, USA.
authors.forename: Allan H
authors.initials: AH
authors.lastname: Friedman
authors.affiliation: Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, USA. Electronic address: fukushima@carolinaneuroscience.com.
authors.forename: Takanori
authors.initials: T
authors.lastname: Fukushima
mesh_terms: D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D004428:Ear Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D007758:Ear, Inner / Q000000981:diagnostic imaging* / Q000601:surgery*; D005260:Female; D006801:Humans; D007759:Labyrinth Diseases / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D035583:Rare Diseases / Q000175:diagnosis / Q000601:surgery; D016896:Treatment Outcome
keywords: Acoustic neuroma; Arachnoid cyst; Cavernous hemangioma; Cochlear schwannoma; Facial schwannoma; Intermedius schwannoma; Internal auditory canal; Lipochoristoma; Meningioma; Mucosa-associated lymphoid tissue (MALT) lymphoma