Unusual occurrence of a pseudo-aneurysm of the middle cerebral artery in apatient with fibromuscular dysplasia

Our patient is the first reported case of pseudo-aneurysm due to the ruptur e of an intracranial artery in the context of fibromuscular dysplasia (FMD) . As we assume that our case is probably not unique, we conclude that this diagnosis may be sometimes overlooked for lack of confirmation either by su rgery or autopsy. The retrospective study of the arteriograms suggests some clues that should be taken into account to foresee the existence of an intracranial pseudo-a neurysm in order to avoid unexpected peroperative difficulties: 1.) the rap id growth of the lesion within a few weeks and 2.) the unusual location of the aneurysmal neck at some distance from a arterial bifurcation.