A case of primary diffuse large B-cell lymphoma of the heart.

Primary cardiac diffuse large B-cell lymphoma (DLBCL) is an exceptionally rare entity in the published literature. We have reported here the case of a 73-year-old Chinese man who presented with intermittent chest tightness as the chief complaint. Echocardiography identified a pedunculated, moderately echogenic mass (approximately 49 × 36 mm) within the left atrium, attached to the interatrial septum and mobile with the cardiac cycle, initially suggestive of a myxoma. The patient underwent surgical resection of the cardiac mass without any preoperative diagnosis. Histopathological examination confirmed DLBCL. Notably, the patient received neither postoperative radiotherapy nor chemotherapy. At nearly 3 years of follow-up, he remains alive with a favorable prognosis and sustained disease-free survival.