title: Anterior inferior cerebellar artery aneurysms mimicking vestibular schwannomas.
abstract: OBJECTIVE
  Unruptured anterior inferior cerebellar artery (AICA) aneurysms are rare but potentially lethal cerebellopontine angle (CPA) lesions that may be misdiagnosed as vestibular schwannomas when they present with vestibulo-cochlear symptoms.
  
  
  METHODS
  We report two cases of unruptured but symptomatic AICA aneurysms initially referred to us as atypical vestibular schwannomas requiring surgery. Two discriminant MR features are described.
  
  
  RESULTS
  One patient refused treatment. The other was successfully treated by coil occlusion.
  
  
  CONCLUSIONS
  Caution is advised before suspecting a CPA mass to be a purely extra-canalicular schwannoma, given its extreme rarity. Deafness and cerebellar ischemia may be prevented if AICA aneurysms are correctly identified preoperatively. In the absence of specific arterial imaging, two MR features may distinguish them from vestibular schwannomas: (1) the absence of internal auditory canal enlargement and (2) the "blurry dot sign," representing blood flow artefacts on pre- and postcontrast studies.
authors: Department of Neuroradiology, Hôpital Lariboisière, Paris, France.
authors: Aïda Kawkabani
authors: AK
authors: Marchini
authors: Pascal J
authors: PJ
authors: Mosimann
authors: Jean-Pierre
authors: JP
authors: Guichard
authors: Monique
authors: M
authors: Boukobza
authors: Emmanuel
authors: E
authors: Houdart
mesh_terms: D000328:Adult; D002531:Cerebellum / Q000098:blood supply* / Q000473:pathology* / Q000601:surgery; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000473:pathology* / Q000601:surgery*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000175:diagnosis* / Q000601:surgery*; D016896:Treatment Outcome
keywords: AICA aneurysms; MRI; vestibular schwannoma mimicks