Unusual lamellar calcifications in two rare cases of splenic aneurysms associated with fibromuscular dysplasia

Fibromuscular dysplasia (FMD) of the splenic artery is a rare underdiagnosed condition. Here, we report two cases of FMD affecting the splenic artery: one alone and one concomitantly with the renal artery. Histology revealed fibromuscular thickening of the media layer alternating with a circumferential calcification of the whole artery thickness. Ultrastructurally, FMD showed matrix vesicles and dense bodies in the extracellular matrix. A diagnosis of FMD with calcification was made. This is the first report to document circumferential lamellar calcifications alternating with the more typical fibrotic medial areas in the rare FMD localized to splenic artery.