Variation of a Persistent Primitive Hypoglossal Artery (PPHA) as Incidental Finding in the Diagnostic Clarification of Cerebral Vasculopathy Associated with Intracranial Vasculitis

We present a very rare variation of a persistent primitive hypoglossal artery (PPHA) arising from the internal carotid artery, detected during a diagnostic angiography. A 50-year-old female patient was admitted with an atypical intracranial hematoma in the left frontal lobe. Catheter angiography revealed intracranial vasculopathy with segmental stenoses, a small aneurysm of the right internal carotid artery bifurcation and a "string of beads" appearance of the left carotid artery, consistent with fibromuscular disease. On the left side, a vertebral artery ending in the posterior inferior cerebellar artery (PICA) was detected, whereas on the right side the vertebral artery was aplastic. During selective angiography of the right common carotid artery, a persistent hypoglossal artery was seen supplying the basilar artery. The literature of persistent embryonal carotid-vertebrobasilar anastomosis and their anatomical variations is discussed with respect to clinical importance for ischemia, interventional procedures, and surgery.