Posterior inferior cerebellar artery aneurysm associated with persistent primitive hypoglossal artery.

A 49-year-old woman presented with subarachnoid hemorrhage (SAH) from an aneurysm associated with a persistent primitive hypoglossal artery (PPHA) manifesting as sudden onset of headache, but without neurological deficits. Conventional computed tomography (CT) of her head showed no abnormality but lumbar tap indicated SAH. Three-dimensional (3D)-CT angiography showed a PPHA originating from the internal carotid artery and an aneurysm of the posterior inferior cerebellar artery at the junction with the remnant hypoplastic vertebral artery. 3D-CT angiography was essentially useful for presurgical planning to determine the extent of craniotomy and the space for possible temporary clipping, and confirmed the diagnosis of aneurysmal SAH. The aneurysm was clipped and she returned to her job 4 weeks later. Cerebral angiography is the golden standard technique to diagnose PPHA, but 3D-CT angiography can be recommended for presurgical evaluation, especially in patients with complex and anomalous anatomical structures.