Delayed aneurysm formation following surgery for a giant serpentine aneurysm.

We report a case of a giant serpentine aneurysm of the right middle cerebral artery (MCA) that was treated by total excision of the aneurysm with cerebral blood flow control management. Four years later the patient presented with a three month history of headache and angiograms showed a new aneurysm on a different branch of the MCA which is thought to have been caused by the previous surgical dissection.