ABSTRACT
The case was a 77-year-old woman with a history of coronary artery bypass surgery 9 years earlier. After the surgery, aortic stenosis appeared and gradually progressed. During follow-up, she presented with a high degree of mitral annular calcification (MAC). A mobile verrucous mass in the left ventricle attached to the calcified posterior mitral annulus. We replaced the aortic valve and resected the mass (size, 3×26 mm). The mass with a club-shape was hard but fragile. Pathological examination revealed that it was a calcified substance without cell components covered with a thin membrane. Immunostainings with CD31 and Factor VIII-related antigen, a vascular endothelial cell marker, were both positive. Thus, the resected mass was diagnosed as a detached calcified mitral annulus. In order to avoid embolic events, early resection would be appropriate for an MAC-related mobile mass.