Vascular anomaly at the craniocervical junction presenting with sub arachnoid hemorrhage: Dilemma in Imaging Diagnosis, Endovascular Management and Complications.

We present a case of a ruptured vertebral artery dissecting aneurysm that mimicked a presumed vascular anomaly by CTA (Computerized Tomographic Angiography). A parenchymal arteriovenous malformation (AVM) or a dural arteriovenous fistula (DAVF) at the craniocervical junction can present with a subarachnoid hemorrhage and cannot be differentiated from a vertebral artery dissection by non invasive imaging. Catheter based cerebral angiography revealed a dissecting pseudoaneurysm of a diminutive right vertebral artery terminating in the posterior inferior cerebellar artery (PICA) that to our knowledge has not been previously reported. NBCA (N-Butyl Cyanoacrylate) embolization of the pseudoaneurysm lumen and sacrifice of the parent vessel resulted in cerebellar infarction, requiring an emergent decompressive craniectomy. The patient recovered to a functional neurologic status.