Two Cases of Fenestration of the Middle Cerebral Artery associated with Aneurysms

Abstract

Two cases of fenestration of the middle cerebral artery(MCA)associated with aneurysms were reported. Case 1 : A 60-year-old female suddenly became unconsious. Left carotid angiography demonstrated a fenestration of the sphenoidal segment of the left MCA and 3 aneurysms, in the bifurcation of the left MCA, in the anterior communicating artery and in the left anterior cerebral artery, were also demonstrated. Surgical intervention was performed on the day of the onset, and all aneurysms were successfully clipped. Case 2 : A 53-year-old female was admitted to our hospital complaining of loss of consciousness. Cerebral angiography demonstrated a fenestration of the sphenoidal segment of the left MCA and an aneurysm at the distal end of the fenestration, and a marked dilatation of the bifurcation of the right MCA. A fenestration of the left MCA was confirmed and an unruptured aneurysm was found arising from the distal end of the fenestration. In tha literature, fenestration of the MCA has been reported in 32 cases, and concomitant aneurysms were found in 21 of these. In most cases, the aneurysms arose from the ipsilateral artery of the fenestration or from the anterior communicating artery. Moreover, a defect in the media at both the proximal and distal ends of the fenestrations has been reported in autopsy cases. From these findings, it is suggested that maldevelopment of intracranial arteries plays an important role in the pathogenesis of the aneurysms as well as in the fenestration pathology itself.