Aneurysm of the Left Middle Cerebral Artery Caused by Myxoid Degeneration of the Vessel Wall

Background Myxoid degeneration of arterial walls may result in dissection and dissecting aneurysms in extracranial and intracranial portions of cerebral arteries. Rarely, saccular aneurysms may also develop on that basis, but thus far these have only been reported in the cervical portions of the carotid arteries. We describe a case of a nondissecting aneurysm of the left middle cerebral artery caused by myxoid degeneration of the media. Case Description A 39-year-old man had acute onset of frontal headache and neck stiffness. Computed tomographic scan and lumbar puncture established the presence of sub-arachnoid hemorrhage. Angiography demonstrated a left mid-dle cerebral artery aneurysm. This was clipped and the wall Intracranial aneurysms have a spectrum of causes.The most common variant is the so-called congen-ital saccular aneurysm, which is believed to de-velop on the basis of focal developmental absence of th