先天性脳動脈瘤との鑑別が困難であった外傷性前大脳動脈瘤の1例

Traumatic Anterior Cerebral Artery Aneurysm Difficult to Distinguish from Congenital Cerebral Aneurysm:Case report

I．はじめに

　外傷に起因する外傷性脳動脈瘤は全脳動脈瘤の0.5—2％と^2,3,15），比較的まれではあるが，一度破裂すると非常に予後不良であり^2,3），早期に発見し適切なる処置を施すことが心要である^4,12）．しかし，その診断はしばしば困難で，外傷後一定期間を経てから動脈瘤の破裂によりはじめて発見されることが多く，破裂前に診断されることは少ない．今回，われわれは受傷直後より脳内に大きな血腫を形成し，先天性動脈瘤との鑑別が困難であった前大脳動脈末梢部の外傷性動脈瘤の症例を経験したのでその診断および病因を中心に文献的考察を加えて報告する．

We report the case of a 29-year-old woman in whom a saccular aneurysm of the distal anterior cerebral artery developed following head trauma due to a car accident. She was semicomatose on admission but had no lateralizing motor signs. Reflexes were symmetrical, with bilateral extensor toe sign. X-ray of the skull showed no fracture but CT scans demonstrated a large frontal hematoma and interhemispheric bleeding. Initial cerebral angiography performed within 12 hours of trauma showed a small protrusion on the precallosal Portion of the left pericallosal artery with no branching point nearby. Angiography was repeated on the 9th day after admission and confirmed the presence of a saccular aneurysm of the pericallosal artery, which had been visible as a small protrusion on the initial angio-gram. Traumatic aneurysm was suspected and success-ful neck clipping of the aneurysm was performed on the 14th day. Preoperative CT and angiographic find-ings could not rule out a congenital aneurysm but the histological study of the specimen confirmed that it was a traumatic false aneurysm. We discussed the diagnosis and the etiology of posttraumatic aneurysm.