Cerebral berry aneurysm Middle cerebral artery berry aneurysm 2026-02-08T15:44:41Z A small, sac-like aneurysm (outpouching) of the middle cerebral artery (MCA). MCA berry aneurysms may occur at the MCA bifurcation, on the anterior communicant artery, the anterior cerebral artery, the internal carotid artery, or on the posterior communicant artery.