Rare variant of persistent primitive hypoglossal artery, arising from the external carotid artery.

A 63-year-old man presented with an extremely rare variant of persistent primitive hypoglossal artery (PHA), which was found incidentally during examination for a contralateral asymptomatic internal carotid artery (ICA) stenosis. This anastomotic vessel arose from the external carotid artery, not the ICA, and joined the vertebrobasilar artery through the hypoglossal canal. Persistent PHA is rare and the reported incidence is 0.027-0.26%. Recognition of the existence of this variant vessel and preservation during neuroradiologic intervention or surgery is important to prevent possible ischemic complications.