BASILAR ARTERY ANEURISM WITH SUB-ARACHNOID HAEMORRHAGE
Incidental finding in a 78 year old man who died from myocardial infarction.
The specimen consists of a brain which has been sliced in a horizontal plane and mounted to display the inferior surface. The vessels at the base of the brain are extensively involved by atheroma with increased tortuosity and cylindrical dilation of the basilar artery. At the termination of the left vertebral artery and the proximal portion of the basilar there is gross saccular aneurismal dilation. A cut through the proximal basilar artery aneurism reveals marked deposition of laminated thrombus. Although a site of rupture cannot be positively identified, extravasation of blood into the subarachnoid space can be seen in the inter peduncular fossa olfactory grooves and on the cut surface in both insulae. The lateral ventricles appear slightly dilated.