Ruptured aneurysm at the origin of duplication of the middle cerebral artery--case report.

A 28-year-old male presented with a rare case of an aneurysm at the origin of duplication of the middle cerebral artery manifesting as subarachnoid hemorrhage. Preoperative angiography revealed duplication of the right middle cerebral artery and an aneurysm at its origin, which was successfully clipped. He was discharged with no neurological deficits. Congenital factors may be more important in the etiology of aneurysms associated with this anomaly.