中大脳動脈末梢部紡錘状未破裂脳動脈瘤の1例

A Case of Unruptured Fusiform Aneurysm in a Middle Cerebral Artery Branch

Ⅰ．はじめに

　紡錘状脳動脈瘤は，囊状動脈瘤に比べ稀で，椎骨脳底動脈系に多くみられる．中大脳動脈の紡錘状動脈瘤に関してはspontaneous fusiform middle cerebral artery aneurysmという概念が存在する²⁾が，報告は少なく，自然歴，治療方法ともに不明な点が多い．今回，われわれは短期間で急速に発生，増大した中大脳動脈末梢部の紡錘状未破裂脳動脈瘤の1例を経験したので報告する．

　We report a case of a 55-year-old female presenting with headache. Neuroradiological investigations revealed a fusiform aneurysm at the M3 part of the right middle cerebral artery. The aneurysm rapidly developed in the course of one year. She underwent a craniotomy for superficial temporal artery middle cerebral artery bypass (STA-MCA bypass) and resection of the aneurysm. Pathological examination suggested that atherosclerosis was a predisposing factor for aneurysm formation. Although she had developed transient dysarthria and left-hand clumsiness after the operation,she was able to be discharged after 26 days with no neurological deficits. On reviewing the literature,fusiform aneurysms seem to be an important cause of subarachnoid hemorrhage and cerebral infarction of unverified origin. Etiology and treatment of spontaneous fusiform aneurysms in a branch of the middle cerebral artery are also discussed.