[Arterial fibromuscular dysplasia as an unexpected cause of death in adults].

In a 38-year-old woman, arterial hypertension was diagnosed a few weeks before her death. She died unexpectedly before a diagnostic clarification of the cause was possible. Autopsy revealed an arterial fibromuscular dysplasia with manifestation in both common iliac arteries, both renal arteries, the celiac trunk and the splenic artery. Both renal arteries displayed stenotic dissecant aneurysms which were the cause of the arterial hypertension. As a rare and lethal complication of fibromuscular dysplasia, a ruptured saccular aneurysm was found in the splenic artery. Histologically, the vascular alterations were a combination of medical fibromuscular dysplasia (type II) and periarterial or adventitial fibroplasia (type III). On the basis of the immunohistochemical detection of abundant lysozyme-positive cells, the periarterial fibroplasia appears to be a secondary chronic granulating and cicatricial reaction and not a separate form of fibromuscular dysplasia.