An aneurysm at the site of the fenestration of the middle cerebral artery in a patient with multiple aneurysms: A case report

BACKGROUND: Middle cerebral artery (MCA) fenestration is a very rare anatomical variant of the MCA, incidentally found during magnetic resonance or computed tomography angiography. It has an incidence of 0.6%. Unlike fenestration of the posterior cerebral arterial circulation, fenestration of the anterior cerebral arterial circulation has not been well described. METHODS: We present the rare case of a patient who was admitted for a ruptured aneurysm of the MCA arising at the site of the fenestration of the MCA and also an unruptured fusiform aneurysm of the right posterior communicating artery and a distal anterior cerebral artery (ACA) aneurysm. RESULTS: The patient underwent craniotomy with microsurgical aneurysm clipping and the previously undiagnosed ruptured aneurysm, at the site of the fenestration of the MCA, arose immediately. Postoperatively, the patient awoke without a deficit. After treatment of postoperative bacterial meningitis, he was discharged on the 26(th) postoperative day in good condition without any neurologic deficit. Six months after the first surgery, he was operated for the distal azygos ACA aneurysm. CONCLUSION: Anomalies of the intracranial vasculature are common, and we describe a rare case of left MCA fenestration with an associated ruptured aneurysm at the site of the fenestration. In the literature, cases of fenestration of the MCA are sporadically reported and are only incidental findings.