ABSTRACT
Calcified amorphous tumor (CAT) is a non-neoplastic mass characterized by calcified nodules that was first reported in 1997. It is often associated with dialysis or mitral annular calcification (MAC). CAT is considered a risk factor for systemic embolism, but there has been no report of CAT damaging the native valve tissue and leading to valvular disease. An 81-year-old woman had shortness of breath on exertion starting 1 year previously, and was referred to our hospital with cardiac murmur detected on physical examination. Echocardiography showed evidence of severe mitral valve regurgitation with ruptured chordae tendineae of the posterior leaflet and a poorly mobile club-shaped structure protruding into the left ventricle and appearing to be continuous with MAC. She underwent elective mitral valve repair. A club-shaped calcification originating from MAC was found under the P2 segment, with ruptured P2 chordae tendineae immediately above it and mitral perforation in the contralateral A2 segment, which were likely to have resulted from direct damage by the hard structure. Mitral valve repair was successful with mass resection, triangular resection of the posterior leaflet P2 segment, and closure of the perforation. Histopathological findings of the mass were consistent with CAT, with no evidence of infection or malignancy. CAT may not only cause embolism but also grow while damaging the native valve tissue. It is important to closely follow-up and perform surgery in proper timing.