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

Our patient is the first reported case of pseudo-aneurysm due to the rupture 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 surgery 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-aneurysm in order to avoid unexpected peroperative difficulties: 1.) the rapid growth of the lesion within a few weeks and 2.) the unusual location of the aneurysmal neck at some distance from a arterial bifurcation.