title: An aneurysm rupturing into a middle cranial fossa arachnoid cyst presenting as an intracystic hemorrhage.
abstract: We report a case of an aneurysm rupturing into an arachnoid cyst presenting as a confined intracystic hemorrhage. A 37-year-old man with a history of sporadic headaches for several years complained of a headache of several days' duration. Brain computed tomography and magnetic resonance imaging revealed a cystic lesion in the left side of the middle cranial fossa that included a 3-cm-diameter hematoma in the Sylvian fissure without extracystic hemorrhage. Left carotid artery angiography showed an internal carotid artery-posterior communicating artery (IC-PC) aneurysm and an anterior choroidal artery aneurysm. The cyst wall was excised, and the aneurysms were clipped. The bleeding point was the spot at which the IC-PC aneurysm entered the arachnoid cyst. Right oculomotor nerve palsy developed after surgery, but resolved after 3 months. To the best of our knowledge, this is the only fourth report to date in the literature of a confined aneurysm rupturing into an arachnoid cyst.
authors.affiliation: Department of Neurosurgery, Japanese Red Cross Hospital Ohmori, Tokyo, Japan. jun-sh@jikei.ac.jp
authors.forename: Jun
authors.initials: J
authors.lastname: Shimizu
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Etsuo
authors.initials: E
authors.lastname: Yamazaki
authors.forename: Masaharu
authors.initials: M
authors.lastname: Yasue
mesh_terms: D000328:Adult; D017542:Aneurysm, Ruptured / Q000150:complications / Q000175:diagnosis / Q000473:pathology*; D016080:Arachnoid Cysts / Q000150:complications / Q000175:diagnosis / Q000473:pathology*; D002543:Cerebral Hemorrhage / Q000150:complications / Q000175:diagnosis / Q000473:pathology*; D035301:Cranial Fossa, Middle / Q000098:blood supply / Q000000981:diagnostic imaging / Q000473:pathology*; D003937:Diagnosis, Differential; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications / Q000175:diagnosis / Q000473:pathology*; D008297:Male; D011859:Radiography; D016896:Treatment Outcome