Thalamostriate artery aneurysm within the third ventricle

The authors report the case of a 7-mm saccular aneurysm, located within the third ventricle and arising from the distal portion of a thalamostriate artery. The patient presented with an intraventricular hemorrhage and was treated via a frontotemporal craniotomy with translamina-terminalis approach for resection of the aneurysm. The etiology of the aneurysm was presumed to be idiopathic. Previously only one other third ventricular aneurysm has been reported. An intraventricular aneurysm arising from a perforating artery should therefore be considered as a rare cause of an intraventricular hemorrhage. Potential surgical approaches to third ventricular aneurysms are discussed.