Accessory middle cerebral artery of distal origin associated with an anterior communicating artery duplication that mimicked an aneurysm

Although both accessory middle cerebral artery (MCA) of distal origin and anterior communicating artery (ACoA) duplication are not rare anatomical variations, their combination is extremely rare and there are only a few reports of such combinations.

We report a case of distal origin accessory MCA associated with ACoA duplication diagnosed by magnetic resonance angiography (MRA).

A 63-year-old man visited another hospital for screening examinations for cerebrovascular disease. He was noted to have a possible intracranial aneurysm at the A1–A2 junction of the right anterior cerebral artery on MRA. He was referred to our hospital for its management. More detailed 3-Tesla MRA volume rendering images revealed ACoA duplication, not an aneurysm. MRA also showed the right distal origin accessory MCA arising from the A2 segment distal to the ACoA duplication.

This rare combination of anatomical variations requires careful imaging assessment. MRA volume rendering images were useful in our case.