Occipital bone abnormality causing recurrent posterior circulation strokes. Cronin Carolyn A,Aldrich E Francois,Kittner Steven J Stroke We report the case of a young man with recurrent posterior circulation strokes over the course of 6 years. Standard stroke evaluation was unremarkable until careful review of catheter angiogram and CT angiogram images revealed a bony protuberance from the occiput impinging on the left vertebral artery. Local vessel injury with thrombosis and distal embolization is the presumed etiology of the recurrent infarcts. Surgical removal of this developmental anomaly was accomplished, with no subsequent neurological events. 10.1161/STROKEAHA.110.612176