Distal posterior cerebral artery aneurysm associated with multiple aneurysms.

True congenital peripheral aneurysms of the cerebral arteries are rare and may constitute a special entity. We report a rare case of nonmycotic peripheral aneurysm of the posterior cerebral artery (PCA) found in association with aneurysms of distal middle cerebral artery (MCA), junction between basilar artery (BA) and superior cerebellar artery (SCA) and MCA trunk. Our present case was a 37-year-old man with a history of abrupt loss of consciousness. Cerebral angiography revealed a right PCA aneurysm originating at the junction between the trunk of the PCA and the posterior temporal branch, and also aneurysms of the right distal MCA, at the right BA-SCA junction and at the trunk of right MCA just distal to the anterior temporal artery. Distal PCA aneurysm causing subarachnoid hemorrhage was successfully clipped and all the other aneurysms were treated in a one-stage procedure. Pathological examination of the surgically excised distal PCA aneurysmal sac demonstrated no infectious etiology. There have not been any similar cases showing an association of vascular anomalies with distal PCA aneurysm. This is the only reported case with the association of nonmycotic peripheral aneurysms involving the MCA and PCA.