“…The topic of bone formation in cardiac valves appears infrequently in the literature and usually as small series or single case reports [2,4,5,11], perhaps because surgically resected, calcified valves are not routinely examined histologically. It has been shown that heterotopic bone formation is closely related to the process of calcification, such that its presence has been described particularly in the aortic valve, in the calcified annulus of the mitral valve (annular calcification) and, rarely, in arterial atherosclerotic plaques [3,8,9].…”