Rupture of an anterior thalamoperforating artery aneurysm: Cause of basal ganglia hemorrhage

Rupture of an arteriovenous malformation, bleeding into a neoplasm, and rupture of circle of Willis aneurysms are known causes for hemorrhage within the basal ganglia. On review of the literature, no previous angiographic demonstration of a macroaneurysm arising from a thalamoperforating artery has been uncovered and serves as the basis of our report. A nonhypertensive patient is described in whom the hemorrhage resulted from rupture of a macroaneurysm involving the distal part of an anterior thalamoperforating branch. The precise etiology of this aneurysm remains undisclosed both because of its deep location, which precluded surgery and histopathologic assessment, and because the aneurysm was not visualized on follow-up examination.