Anterior (dorsal) paraclinoid aneurysm: case report.

Saccular aneurysms arising at locations other than arterial divisions have been reported but are extremely rare. Such a case of a previously unclassified paraclinoid aneurysms that arose from the anterior (dorsal) wall of the proximal internal carotid artery is reported. The neck of this aneurysm was located distal to the junction of the ophthalmic artery, which originated in the cavernous sinus. I propose that this aneurysm be classified as an anterior (dorsal) paraclinoid aneurysm.