Bulky Mitral Annulus Caseous Calcification in an Atypical Location.

Mitral annular calcification (MAC) is a commonly observed chronic and degenerative fibrotic process of the base of the mitral valve, usually deemed as an incidental finding. Although initially, MAC was thought to be a consequence of an age-related degenerative process, recent findings suggest other independent contributive mechanisms, such as atherosclerosis and abnormal calcium-phosphorus metabolism. Caseous calcification of the mitral annulus (cMAC) is a rarely described variant of MAC, characterized by an ovoid, focal mass with internal caseous fluid-like calcifications and debris. Differentiating a cMAC from other cardiac masses attached to the mitral annulus may be challenging. A single imaging modality, such as transthoracic echocardiography, may not be sufficient for a clear diagnosis. Therefore, a multimodal imaging approach is necessary, including cardiac tomography computerized imaging and cardiac magnetic resonance (CMR). MAC and cMAC typically affect the posterior mitral annulus, with very few cases in the literature describing the involvement of the anterior annulus. We present a rare case of an anterior mitral annulus caseous calcification found in a CMR performed to evaluate a left atrial mass identified on a transthoracic echocardiogram.