title: Extracranial aneurysm of the distal PICA presenting as isolated fourth ventricular hemorrhage: case report and literature review.
abstract: BACKGROUND
  Posterior inferior cerebellar artery (PICA) aneurysms are relatively uncommon, comprising only 0.5-3% of all intracranial aneurysms. Distal PICA aneurysms are much more uncommon, with more than 200 cases being reported in the literature. The finding of an extracranially located aneurysm of distal PICA is considered a true rarity.
  
  
  RESULTS
  A rare case of extracranially located PICA aneurysm presenting with isolated fourth ventricular hemorrhage is presented and the diagnostic and therapeutic challenges discussed.
authors.affiliation: Department of Neurosurgery, Sina Hospital, Tehran University of Medical Sciences (TUMS), Tehran, Iran.
authors.forename: Mohamad
authors.initials: M
authors.lastname: Shirani
authors.forename: Ali
authors.initials: A
authors.lastname: Abdoli
authors.forename: Maysam
authors.initials: M
authors.lastname: Alimohamadi
authors.forename: Mehdi
authors.initials: M
authors.lastname: Ketabchi
mesh_terms: D000328:Adult; D015901:Angiography, Digital Subtraction; D002531:Cerebellum / Q000098:blood supply* / Q000000981:diagnostic imaging; D002533:Cerebral Angiography; D002552:Cerebral Ventricles; D006470:Hemorrhage / Q000000981:diagnostic imaging / Q000209:etiology* / Q000601:surgery; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed