[A case of infundibular dilatation developed into an aneurysm and rupturing after the rupture of an aneurysm 10 years ago].

A 44-year-old female with subarachnoid hemorrhage caused by the left internal carotid-posterior communicating artery aneurysm rupture was presented. At that time, carotid angiography showed the left internal carotid-posterior communicating artery aneurysm and the right internal carotid-posterior communicating artery portion infundibular dilatation. Neck clipping for left internal carotid-posterior communicating artery aneurysm was done and she was discharged from our hospital without neurological deficit. After 10 years, she suffered a second subarachnoid hemorrhage. Carotid angiography demonstrated the right internal carotid-posterior communicating artery aneurysm developed from the opposite infundibular dilatation. Emergency clipping was performed with three Sugita fenestration clips, because that aneurysm had a very wide neck. We should examine the internal carotid-posterior communicating artery infundibular dilatation with opposite side aneurysms in young females carefully and serially.