“True Fetal Posterior Cerebral Artery”: Rare Variant Mimics AVM on MRI

A “true fetal posterior cerebral artery” is an extremely rare anatomic variant of the cerebral vasculature in which 2 independent posterior cerebral arteries are present; 1 arises from a persistent large primitive anterior choroidal artery and a second arises in the usual fashion. This case report demonstrates this diagnosis made using cerebral angiography in a young woman with nonspecific headaches whose MR imaging brain scan was originally interpreted as a brain arteriovenous malformation or dural arteriovenous fistula. Given the rarity of a true fetal posterior cerebral artery, awareness of this entity may make it discernible on cross-sectional imaging. In addition, it is important to be able to recognize this angiographically because this variant supplies posterior cerebral structures and should not be embolized.