Caseous calcification of the mitral annulus: unusual case of spontaneous resolution.

Mitral annular calcification (MAC) is a common echocardiographic finding. Caseous calcification is a rare variant appearing as a round, tumor-like mass with central echolucent area located in the periannular region. Although occasionally misdiagnosed as a tumor and submitted to exploratory cardiotomy, this lesion appears to carry a benign prognosis.