Fenestration of the middle cerebral artery in a patient who presented with transient ischemic attack

Cerebral artery fenestrations are usually detected incidentally during angiography, have a reported incidence ranging from of 0.03% to 1%, and rarely cause neurological symptoms. They can, however, be associated with aneurysmal dilatation at the proximal or distal end of the fenestration, cerebral arteriovenous malformations, or (rarely) ischemic symptoms. We present a case of a 54-year-old obese woman who presented with a large convex-lens-like fenestration of the right middle cerebral artery (MCA) at the M1 segment (distal to the origin of the temporopolar artery) associated with a transient ischemic attack. The MCA fenestration caused a local change in hemodynamic blood flow, which leads to cerebral ischemia. Magnetic resonance angiography (MRA) also revealed an associated small slit-like fenestration of the basilar artery (BA), hypoplasia of the A1 segment of the right anterior cerebral artery, bilateral fetal posterior cerebral arteries, and bilateral absence of the posterior communicating arteries. To our knowledge, this is the sixth reported case of MCA fenestration with an associated ischemic attack. In our case, fenestrations of the MCA, the BA, and hypoplasia of the A1 segment of ACA were not associated with any aneurysms.