Peripheral superior cerebellar artery aneurysm.

A 48-year-old male harboring a rare peripheral superior cerebellar artery aneurysm presented with sudden severe headache. Neurological examination on admission revealed no deficit except stiff neck. Computed tomography showed subarachnoid hemorrhage. Left vertebral angiography showed an aneurysm at the anterior pontomesencephalic segment (anterior pontine segment) of the left superior cerebellar artery. The neck of the aneurysm was rather high, 10 mm above the biclinoid line. The aneurysm was clipped through an orbitozygomatic transsylvian approach. His postoperative course was uneventful. We recommend this skull base approach especially for high-positioned aneurysms at this segment.