Disappearance of a cerebral aneurysm--an unusual angiographic event.

Spontaneous thrombosis of cerebral aneurysms demonstrated by angiography is infrequent. This article describes angiographically documented spontaneous thrombosis of an intracranial aneurysm at the posterior cerebral-posterior communicating artery junction in a 40-year-old woman. The initial angiogram done on 16th day after an episode of subarachnoid haemorrhage showed a medium sized aneurysm. Subsequent angiograms done on 30th, 40th and 60th day failed to demonstrate the aneurysm. The factors leading to this rare event remain obscure.