くも膜囊胞に合併した破裂脳動脈瘤について

Ruptured Cerebral Aneurysm Associated with Arachnoid Cyst

Ⅰ．はじめに

　くも膜囊胞および脳動脈瘤は，日常診療でも遭遇する機会の多い，いずれもよく知られた病変であり，以前と比べその診断率は向上しているものの両者の共存は比較的稀である^{1,3-8,10-19,22,24-27,30,31)}．

　今回われわれは，以前よりくも膜囊胞を指摘され，破裂脳動脈瘤を合併した稀な2症例を経験したので，文献的考察を加え報告する．

　Cerebral aneurysms and arachnoid cysts are relatively common cerebral malformations and the use of recent modalities has increased their detection rates. However, cerebral aneurysms associated with arachnoid cysts are unusual. We describe two cases of ruptured cerebral aneurysms associated with arachnoid cysts.

　According to previous reports, clinical presentation may sometimes be unusual, as cysts can prevent subarachnoid hemorrhage. Moreover, in some cases, CT may reveal typical arachnoid cysts without subarachnoid hemorrhage, without intracystic hematoma, or with subdural hematoma alone. These clinical presentations and radiologic findings can lead to delayed diagnosis of subarachnoid hemorrhage. Therefore, we should consider the coexistence of arachnoid cyst in case of a warning sign of aneurysm rupture.