Rare variant of persistent primitive hypoglossal artery in magnetic resonance angiography.

We present an extremely rare case of a variant of persistent primitive hypoglossal artery, which was found incidentally in magnetic resonance angiography during an examination for dizziness. This anastomotic vessel arose from the external carotid artery (ECA), not internal carotid artery, and entered the hypoglossal canal to basilar artery. To our knowledge, this is the fourth reported case of the persistent hypoglossal artery arising from the ECA. The possible clinical implications of this anomalous vessel are discussed.