Distal middle cerebral artery aneurysms is a rarely seen encountered condition, constituting 1.1–5% of MCA lesions 1) 2). In a large surgical series of 1012 patients, there were four patients with dMCA 3). In the other large surgical series of 3005 patients, there were 18 patients with dMCA aneurysm 4).
According to Gibo et al., 5) to locate MCA aneurysms the distal vessel was classified into four segments M2 (insular segment), M2–M3 junction, M3 (opercular segment) and M4 (cortical segment).
Clinical findings and surgical approaches of dMCA aneurysm are different from proximal MCA aneurysms. Treatment of those aneurysms is difficult because of their deep location, small size and angio architecture.