Caseous necrosis of the mitral annulus masquerading as an intracardiac mass

Caseous necrosis of the mitral annulus is a rare condition which typically involves the posterior leaflet or annulus. We report the case of a 71-year-old female with extensive comorbidities, presenting with dyspnea and angina, who had an incidental echocardiographic finding of a mass on or near the mitral valve. The mass increased in size over the course of three years and was associated with severe mitral regurgitation. The mass was initially thought to be a myxoma, however, surgical exploration revealed caseous necrosis of the posterior mitral annulus. Following removal of the necrotic tissue and distorted mitral leaflet, a bioprosthetic mitral valve was implanted and the patient recovered uneventfully.