Distal posterior inferior cerebellar artery aneurysm: case report.

The majority of posterior inferior cerebellar artery (PICA) aneurysms are usually found on the bifurcation of the vertebral artery (VA) - PICA junction. Aneurysms arising from more peripheral PICA segments named distal PICA aneurysm are uncommon. The major clinical manifestation is that of an intracranial bleeding and the site of hemorrhage is related to the PICA segment originating the aneurysm. Lesions originating from distal PICA segments, particularly those arising from the telovelotonsillar segment, are associated with hemorrhage extending into the ventricular system, mainly the i.v. ventricle. A case of a 50-year-old woman with sudden headaches and vomiting, and intraventricular hemorrhage (four ventricles) caused by an aneurysm of the telovelotonsillar segment of the PICA, is presented. No signs of subarachnoidal hemorrhage were found in the computerized tomography. The aneurysm was clipped and the patient presented a favorable outcome. Anatomical aspects and clinical series are reviewed.