Persistent Primitive Trigeminal ArteryとMetopismを合併した破裂脳動脈瘤の1例

A Case of Ruptured Aneurysm Associated with Persistent Primitive Trigeminal Artery and Metopism

I．はじめに

　胎生期遺残動脈の一つであるpersistent primitive tri—geminal artery（以下PTAと略す）は脳血管撮影上，0.1—0.3％に見出だされるとされ^12），またその約14％に脳動脈瘤を合併すると言われている^2,6）．また成人にmetopic sutureが遺残した状態は，metopismと呼ばれているが，比較的稀である^3,5）．今回私達は，中大脳動脈瘤破裂によるクモ膜下出血で発症し，PTAとmetopismを合併していた非常に稀な1例を経験したので，若干の文献的考察を加えて報告する．

The authors reported an extremely rare case of rup-tured aneurysm associated with persistent primitive trigeminal artery (PTA) and persistent metopic suture (metopism).

A 46-year-old female suffered sudden onset of a se-vere headache with nausea and vomiting on February 24, 1991. She was transferred to Kagoshima Prefectural Oshima hospital from the other clinic on the next day. She complained only of severe headache on admission, and neurological examination revealed no abnormal findings. Plain craniograms disclosed a persistent meto-pic suture extending from the bregma to the midportion of the frontal bone. Computed tomography demons-trated a mild subarachnoid hemorrhage. The right in-ternal carotid angiograms showed a ruptured aneurysm in the middle cerebral artery. These angiograms also demonstrated PTA originating from the cavernous por-tion of the internal carotid artery and ending at the mid-portion of the basilar artery.

The frequency of angiographic demonstration of per-sistent primitive trigeminal artery is 0.1 to 0.3%. It is well recognized that approximately 14% of patients with PTA also have intracranial aneurysm. The inci-dence of persistent metopic suture in adults is 1-10%. After an extensive review of the literature we have concluded that there has been no case report of a rup-tured aneurysm associated with PTA and metopism. The authors think that, in this case, the coexistence may be only incidental.