Fatal rupture of a thrombosed giant basilar artery aneurysm.

The case of a patient who died from rupture of an aneurysm that had previously been demonstrated to be essentially completely thrombosed is presented. The patient initially presented with sudden clinical deterioration as a result of brainstem compression. A computed tomographic scan showed a giant basilar aneurysm with recent thrombus filling the lumen. Angiography showed only a small irregularity at the top of the basilar artery which may have represented a tiny remnant of the aneurysmal neck. The patient was treated conservatively, and over the next few weeks he improved clinically. Four months later the aneurysm ruptured fatally.