Clinical presentationA 55-year-old woman was admitted to hospital with a2 day history of increasing headaches followed by drows-iness and confusion with vomiting. Her past historyincluded a cerebrovascular accident 11 years previouslywith a residual right hemiparesis. There had been a tran-sient episode of vertigo and left hemi-anesthesia 2 yearsafter this, with no subsequent neurological symptoms orsigns. On admission she was semicomatose but rousablewith an elevated blood pressure of 190/125. On examina-tion she demonstrated signs of her previous cerebrovas-cular accident with pareses of the right sixth, seventh andtwelfth cranial nerves, right sided limb weakness withhyper-reflexia, and bilateral positive Babinski signs. Herrespiration was described as periodic and stertorous. Hercondition continued to deteriorate and she died the fol-lowing day before a diagnosis could be established.Autopsy findingsAt autopsy the body was that of an adult Caucasian femaleof around the stated age of 55 years. Her height was173 cm, weight 71 kg, and body mass index (BMI) 23.7.The major findings were limited to the brain which showedevidence of swelling with gyral flattening. The basilarartery was replaced by a bilocular aneurysm; the main partof the aneurysm measured 4 9 4 9 6 cm (Fig. 1), and asmaller extension measured 1 9 1 9 2 cm (Fig. 2). Theaneurysm contained postmortem blood clot. Sectioning ofthe brain revealed marked symmetrical dilatation of thelateral and third ventricles, in keeping with the effects ofobstruction to cerebrospinal fluid flow, with no macro-scopic evidence of previous infarction (Fig. 3). The spec-imen had been retained for museum display and so nofurther sectioning or sampling for histology had beenundertaken. Moderate atherosclerosis was present in thecoronary arteries and aorta. No other significant underlyingorganic diseases were present which could have caused orcontributed to death.Cause of deathBrainstem compression from a large aneurysm of thebasilar artery.Museum referenceThis case, # 19393, can be located at the Hans SchoppeMuseum of Pathology at the School of Medical Sciences,Medical School North, The University of Adelaide, FromeRd, Adelaide, SA, Australia.DiscussionAneurysms representing pathological areas of arterialdilation may be found in all parts of the cerebral vascula-ture [1]. The incidence of cerebral aneurysms and associ-ated subarachnoid hemorrhage varies among countries,with high rates in both Japan and Finland [2, 3]. The