Calcified amorphous tumor with caseous calcification of mitral annulus in hemodialysis patients

Mitral annular calcification (MAC) is a common finding, especially among the elderly. Caseous calcification of the mitral annulus (CCMA) is a rare variant of MAC. Calcified amorphous tumor (CAT) is an extremely rare non-neoplastic cardiac tumor accompanied by calcification and is often associated with MAC. We encountered two patients with end-stage renal failure in whom a cardiac CAT developed on the mitral annulus. In both patients, preoperative examination showed MAC of the posterior mitral annulus and a mobile mass attached to the MAC. CAT and CCMA were considered, and surgical resection was performed because of a high risk of systemic embolization. Intraoperatively, the mobile mass was associated with the CCMA. The CCMA with the mass was entirely removed, and the diagnosis of CAT was histologically confirmed. We herein report these two cases of CAT arising from CCMA in patients undergoing hemodialysis and propose the characteristic imaging features and operative findings.