Caseous calcification is usually an incidental finding on the atrioventricular valvular annulus. The exact mechanism of pathogenicity for the caseous calcifications has not been defined yet. Differential diagnosis includes vegetation, thrombus, or metastatic tumors. We presented a case of a large tricuspid mass as an incidental finding by transthoracic echocardiography in a patient with metastatic colon cancer. The distinction between caseous calcification and metastatic tumor was made based on the typical location of calcification, possible extension to the whole mitral annulus, well-defined borders, and the internal echolucent area.