Big MAC: caseous calcification of the mitral annulus referred for possible cardiac tumor.

A 73-year-old woman was found to have a 1.4 × 3.0 cm heterogeneous echodensity with smooth borders and central echolucency associated with a dynamic left ventricular outflow tract gradient and episodic chest pain. Although mitral annular calcification is a common manifestation, this case represents caseous calcification of the mitral annulus, which is a rare variant with an estimated prevalence of 0.068%. It should not be misinterpreted as an intracardiac tumor, abscess or cyst, as was the initial assumption in this case. The implications of the dynamic left ventricular outflow tract obstruction as the etiology of her episodic chest pain and potential dynamic changes in structure with calcium levels are further elucidated in this case.