title: Parenchymal perianeurysmal cystic changes in the brain: report of five cases.
abstract: OBJECTIVE
  To describe parenchymal perianeurysmal cystic changes in the brain.
  
  
  METHODS
  Among 247 patients with cerebral aneurysms described in the medical or radiologic records in three institutions, five had perianeurysmal cystic changes. These were evaluated with computed tomography or magnetic resonance (MR) imaging and were categorized according to size, appearance, and the presence of hemosiderin deposit. Confirmation at stereotactic needle biopsy was available in one case.
  
  
  RESULTS
  Perianeurysmal cysts comprised multiple clustered cysts in three cases and a unilocular cyst in two, and diameters were 1.5-3.5 cm. Hemosiderin was depicted at MR imaging in one unilocular cyst. Associated aneurysms had diameters of 0.7-4.0 cm, and prominent aneurysmal thrombosis and calcifications were seen in two cases. Findings at stereotactic needle biopsy were of mild reactive gliosis. At long-term follow-up in two patients, the cystic regions were stable.
  
  
  CONCLUSIONS
  Parenchymal perianeurysmal cysts are rare and may display various morphologic characteristics from unilocular to multilocular. Since there may or may not be evidence of previous hemorrhage, other mechanisms such as abnormal angiogenesis factors may play a role.
authors.affiliation: Departments of Diagnostic Radiology, Gunma University School of Medicine, Maebashi, Gunma, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Sato
authors.forename: G
authors.initials: G
authors.lastname: Sze
authors.forename: I A
authors.initials: IA
authors.lastname: Awad
authors.forename: C M
authors.initials: CM
authors.lastname: Putman
authors.forename: T
authors.initials: T
authors.lastname: Shibazaki
authors.forename: K
authors.initials: K
authors.lastname: Endo
mesh_terms: D000328:Adult; D001706:Biopsy; D001921:Brain / Q000473:pathology*; D001927:Brain Diseases / Q000175:diagnosis* / Q000473:pathology; D002114:Calcinosis / Q000175:diagnosis; D002533:Cerebral Angiography; D002543:Cerebral Hemorrhage / Q000175:diagnosis; D003560:Cysts / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D005911:Gliosis / Q000175:diagnosis; D006485:Hemosiderin / Q000032:analysis; D006801:Humans; D002532:Intracranial Aneurysm / Q000175:diagnosis* / Q000473:pathology; D020767:Intracranial Thrombosis / Q000175:diagnosis; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000175:diagnosis; D012189:Retrospective Studies; D013238:Stereotaxic Techniques; D014057:Tomography, X-Ray Computed
chemical_list: D006485:Hemosiderin