title: Cavernous malformation presenting as an extra-axial cerebellopontine angle mass: case report.
abstract: OBJECTIVE
  We describe a rare case of an extra-axial cavernoma of the cerebellopontine angle without internal auditory canal involvement and with an unusual appearance on preoperative magnetic resonance imaging (MRI). Only three cases of cerebellopontine angle cavernomas have been previously reported, and none of these reports included preoperative MRI.
  
  
  METHODS
  A young man presented with subacute left facial hypesthesia and chronic asymmetrical sensorineural hearing loss. MRI revealed a mass, which was isointense on T1- and T2-weighted images, with evidence of hemorrhage (methemoglobin and hemosiderin). The lesion did not enhance after the injection of gadolinium.
  
  
  METHODS
  The lesion was removed without difficulty by a suboccipital approach, with intraoperative electrophysiological monitoring of facial and cochlear nerves. Facial paresis cleared postoperatively.
  
  
  CONCLUSIONS
  The present case suggests that the appearance of cerebelopontine angle cavernomas as revealed by MRI may be similar to that of intraparenchymal cavernomas. This is in contrast to previously reported cases of extra-axial cavernomas at other sites. Evidence of hemorrhage in an extra-axial lesion revealed by MRI suggests a possible diagnosis of cavernoma.
authors.affiliation: Department of Radiology, Sunnybrook Health Science Centre, University of Toronto, North York, Ontario, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Kim
authors.forename: D W
authors.initials: DW
authors.lastname: Rowed
authors.forename: G
authors.initials: G
authors.lastname: Cheung
authors.forename: L C
authors.initials: LC
authors.lastname: Ang
mesh_terms: D000328:Adult; D002528:Cerebellar Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D002530:Cerebellopontine Angle / Q000473:pathology / Q000601:surgery; D002543:Cerebral Hemorrhage / Q000175:diagnosis / Q000473:pathology / Q000601:surgery; D006392:Hemangioma, Cavernous / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D014057:Tomography, X-Ray Computed