Spontaneous Perforation of Anterior Choroidal Artery with Resultant Pseudoaneurysm Formation: Unusual Cause of Subarachnoid Hemorrhage.

Abstract

Subarachnoid hemorrhage resulting from spontaneous perforation of a small intracranial vessel, with resultant pseudoaneurysm formation, has not been widely reported in the literature. We present the case of a 71-year-old patient with rupture of a small aneurysm of a duplicated left anterior choroidal artery causing an acute third nerve palsy. The aneurysm was not able to be treated endovascularly without sacrifice of the parent vessel. At surgery, a pseudoaneurysm was seen completely separate from the parent vessel, which was actively bleeding through a hole in the vessel. The pseudoaneurysm was indenting the oculomotor nerve. After confirmation of adequate collateral flow, the abnormal segment of vessel was trapped and the pseudoaneurysm removed with surrounding clot. The patient's cranial nerve palsy resolved. This case illustrates an unusual sequela of subarachnoid hemorrhage presenting a unique challenge in surgical management.