[Bilateral pericallosal artery aneurysms in a mirror position].

A rare case of ruptured pericallosal (distal anterior cerebral) artery aneurysm, associated with another one in a mirror position is reported in this paper. The angiograms disclosed no variant vessels, such as azygos anterior cerebral artery and/or supreme anterior communicating artery. This patient, a 47-year-old woman, was successfully treated by surgery without any complication. The literature concerned is reviewed and possible pathogenesis of cerebral aneurysm discussed briefly.