title: Uncommon lesions presenting as tumors of the internal auditory canal and cerebellopontine angle.
abstract: OBJECTIVE
  The aim of this study was to identify distinguishing characteristics of uncommon lesions of the cerebellopontine angle (CPA) and internal auditory canal (IAC) in order to attain the correct diagnosis and thus formulate an appropriate therapeutic protocol.
  
  
  METHODS
  A retrospective chart analysis was performed on all patients with surgically managed lesions of the IAC and CPA referred to neuropathology from January 1985 to April 1996.
  
  
  METHODS
  All patients were treated by New York University faculty at a tertiary referral center.
  
  
  METHODS
  Among 426 surgical cases identified, 384 patients (90.1%) with acoustic neuromas and 18 patients (4.2%) with meningiomas were excluded. The remaining 24 cases, involving 17 women and seven men with a median age of 34 years, were analyzed.
  
  
  METHODS
  Most patients underwent audiovestibular evaluations, as well as magnetic resonance imaging (MRI) and computed tomographic (CT) scanning, and all patients underwent neurotologic surgery as part of their management protocol.
  
  
  METHODS
  Correlating patient presentation, preoperative imaging, and surgical findings often identified distinguishing characteristics of unusual CPA and IAC lesions.
  
  
  RESULTS
  Unusual lesions identified at the CPA and IAC included: four epidermoids, four lipomas, two facial neuromas, two arachnoid cysts, two choroid plexus papillomas, two metastatic adenocarcinomas, one metastatic neuroblastoma, one ependymoma, one lymphoma, one cholesterol cyst, one angioleiomyoma, one venous hemangioma, one cavernous angioma, and one pontine glioma.
  
  
  CONCLUSIONS
  Preoperative tumor differentiation based on the patient history, physical examination, audiovestibular testing, CT, and MRI help the surgeon to formulate an appropriate treatment protocol.
authors.affiliation: Department of Otolaryngology, New York University Medical Center, New York, USA.
authors.forename: D
authors.initials: D
authors.lastname: Kohan
authors.forename: L L
authors.initials: LL
authors.lastname: Downey
authors.forename: J
authors.initials: J
authors.lastname: Lim
authors.forename: N L
authors.initials: NL
authors.lastname: Cohen
authors.forename: E
authors.initials: E
authors.lastname: Elowitz
mesh_terms: D000328:Adult; D002528:Cerebellar Neoplasms / Q000150:complications / Q000175:diagnosis*; D002530:Cerebellopontine Angle; D003937:Diagnosis, Differential; D004428:Ear Neoplasms / Q000150:complications / Q000175:diagnosis* / Q000473:pathology*; D007758:Ear, Inner / Q000473:pathology*; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012189:Retrospective Studies; D014012:Tinnitus / Q000175:diagnosis / Q000209:etiology