Spontaneous Subarachnoid Hemorrhage From a Pure Pial Arterial Malformation in the Lateral Cerebellomedullary Junction: Clinical Images with a Surgical Video.

Pure pial arterial malformations (PAMs) are poorly understood owing to the limited number of reported cases. Because PAMs have been thought to have a benign natural history, they have generally been managed conservatively, unlike arteriovenous malformations or arteriovenous fistulas. In the present report, we have described a spontaneous subarachnoid hemorrhage from the rupture of a PAM at the cerebellomedullary junction. This hemorrhage was surgically treated using clip trapping.