Mediastinal diffuse large B-cell lymphoma invading the left atrium mimicking coronary artery disease with a mural thrombus.

A left atrial mass associated with coronary artery disease is often diagnosed as a mural thrombus rather than other possible etiologies such as benign primary cardiac tumor (myxoma, lipoma), a malignant primary cardiac tumor (sarcoma, lymphoma), or secondary involvement for extracardiac tumors. Malignant lymphoma initially presenting as intracardiac masses is very rare. Chest computed tomography with contrast enhancement and cardiac magnetic resonance may be the best methods for distinguishing primary cardiac tumors from direct extension from adjacent mediastinal structures. We report the case of a 59-year-old man with incidentally found mediastinal diffuse large B-cell lymphoma invading the left atrium, which presented with coronary artery disease and a left atrial mass. Improvement in cardiac ventricular function heart after coronary artery bypass grafting may provide the patient with a better chance of receiving an adequate dose of chemotherapy.