Fenestration of the middle cerebral artery and aneurysm at the site of the fenestration.

The authors report the case of a patient who presented a ruptured aneurysm of the anterior communicating artery and an unruptured aneurysm of the middle cerebral artery arising at the site of a fenestration of the MCA. The fenestration was undiagnosed on the preoperative angiogram but discovered during the surgery carried out for clipping of the aneurysms. In the literature, cases of fenestration of the MCA are sporadically reported and are incidental findings; an aneurysm may be associated on an artery other than the fenestrated MCA; an aneurysm arising at the site of the MCA fenestration is a very rare occurrence.