Aneurysm of a duplicate middle cerebral artery

Anatomic middle cerebral artery (MCA) anomalies are rare, but each of the described variants (eg, duplicate, fenestrated, accessory) can be of clinical significance.

A 34-year-old man with a history of left hemispheric stroke was found to have an aberrant, early-arising duplicate left M1 segment of the MCA with an associated asymptomatic fusiform aneurysm. The patient was treated with a superficial temporal artery (STA) to distal MCA bypass followed by surgical trapping of the aneurysm.

Intraoperative and follow-up angiography performed postoperatively at 3 months showed complete isolation of the aneurysm from the circulation and patency of the bypass graft. The postoperative course was uneventful with the exception of a craniotomy flap infection, which was effectively managed with intravenous antibiotics, flap removal, and subsequent use of a fabricated replacement.

This rare case is presented and used as a framework for a brief discussion of the literature regarding both variant MCA anatomy and treatment considerations for these anomalies when associated with an aneurysm.