Cardiac mesothelial/monocytic-incidental-excrescence: more than an artifactual lesion?

Mesothelial/monocytic incidental cardiac excrescence (MICE) is a benign finding made up of a mixture of cuboidal mesothelial cells, histiocytes and fibrine and is mainly found incidentally during open heart surgery, commonly after cardiac catheterization. Clinical importance of this lesion has been emphasized because of its potential confusion with malignancies, especially with metastatic carcinoma. We report a case of an asymptomatic 72-year-old man with incidental finding of a pericardial effusion and a small mass attached to the left appendage.