くも膜下出血を繰り返した多発性動脈硬化性紡錘状脳動脈瘤の1例

A Case of Multiple Atherosclerotic Fusiform Cerebral Aneurysms with Repeated Subarachnoid Hemorrhage

Ⅰ．はじめに

　脳動脈瘤は外観の形態により囊状と紡錘状に分けられるが，後者の頻度は3〜13%と推定されている¹⁾．瘤破裂は囊状動脈瘤が大多数で，紡錘状動脈瘤の破裂もあるが多くは解離性動脈瘤であり，非解離性紡錘状動脈瘤の疫学は必ずしも明確ではない．紡錘状脳動脈瘤，特に動脈硬化性動脈瘤はその自然歴や治療適用に不明な点が多い．今回われわれは，初回治療の9年後に再破裂した非解離性紡錘状動脈瘤に対し，母血管閉塞に血行再建術を併用した症例を経験したので報告する．

　Pure fusiform aneurysms without dissection are considered to have a low risk of rupture. Furthermore, aneurysm wall with atherosclerotic change tends to be less susceptible to rupture. We present a rare case of multiple atherosclerotic fusiform aneurysms associated with repeated subarachnoid hemorrhage（SAH）during a 9-year observation period. A 34-year-old woman was admitted to our hospital because of SAH. SAH with a temporal hematoma due to a fusiform aneurysm of the right middle cerebral artery（MCA）was detected using computed tomography（CT). Associated fusiform aneurysms were observed in the left posterior cerebral artery（PCA）and the left MCA. The right MCA aneurysm was occluded with angioplastic clipping. Eight years after the first onset, angioplastic clipping was performed on the other two fusiform aneurysms because of their growth. Intraoperative findings showed atherosclerotic change in the parent artery wall, similar to the right MCA aneurysms. The right MCA aneurysm ruptured again 1 year later. The aneurysm was treated with proximal occlusion combined with a bypass from the occipital artery to the distal MCA. The patient was in a stable state, although, she was disabled because of SAH damage. The effects of atherosclerotic fusiform aneurysms, which are rarely encountered, are not well known. Some studies have reported the risk of hemorrhage from these aneurysms. This case suggests the necessity of long-term follow-up for the prediction of aneurysm growth and bleeding. Moreover, proximal occlusion combined with an external bypass is better for the treatment of this type of aneurysm because angioplastic clipping is not curative.