[Ruptured Aneurysm of Bihemispheric Anterior Cerebral Artery A1-A2 junction:A Case Report].

We report a rare case with a ruptured aneurysm of the bihemispheric anterior cerebral artery(ACA), a rare anomaly of the ACA. A 50-year-old female experienced a sudden onset of severe posterior cervical pain. CT revealed diffuse subarachnoid hemorrhage(SAH)and intra cerebral hemorrhage of the left rectal gyrus. Cerebral angiography showed the left bihemispheric ACA and hypoplasia of the right ACA. A saccular aneurysm was indicated at the A1-A2 junction of the left bihemispheric ACA. A neck clipping was performed completely through the right transsylvian approach. There are several reports of an aneurysm with bihemispheric ACA, but all cases are distal ACA aneurysms. In this case, the aneurysm was proximal to the bihemispheric ACA and such aneurysms have not been reported.