Replaced right posterior cerebral artery associated with ipsilateral superior cerebellar artery type persistent trigeminal artery variant diagnosed by magnetic resonance angiography.

Purpose: To describe a case in which a right replaced posterior cerebral artery (PCA) was associated with an ipsilateral superior cerebellar artery (SCA) type persistent trigeminal artery (PTA) variant.

Methods: A 53-year-old man who had been diagnosed with chronic dissection of the left vertebral artery (VA) 4 months previously underwent follow-up magnetic resonance (MR) angiography using a 3-Tesla scanner.

Results: MR angiography showed a slightly dilated left VA at the terminal segment without interval change. An artery arising from the cavernous segment of the right internal carotid artery (ICA) and continuing to the right SCA without connection to the basilar artery is indicative of the SCA type PTA variant. There was also a large artery arising from the supraclinoid segment of the right ICA and continuing to the right PCA. In addition, a tiny artery arose from the right ICA proximal to the origin of the large artery. There were no tiny arteries arising from the right ICA distal to the origin of the large artery. Therefore, the tiny artery is considered to be a hypoplastic posterior communicating artery and the large artery is considered to be a replaced PCA.

Conclusion: A replaced PCA is an extremely rare variation, from which all branches of the PCA arise from the anterior choroidal artery. The SCA type PTA variant is also rare. This is the first report of a case of a combination of these two variations; however, they had no developmental relationship. Thus, our patient incidentally had two extremely rare ipsilateral variations.