[Cardiac and breast diffuse large B-cell lymphoma with pericardial effusion and AV-block].

Primary cardiac lymphoma is extremely rare and is associated with a poor prognosis. In most cases, cardiac involvement occurs as a late symptom and the diagnosis is thus delayed. We herein report a 35-year-old woman with cardiac diffuse large B-cell lymphoma (DLBCL) with breast infiltration. The patient was admitted to our hospital based on an initial presentation with dyspnea on exertion, chest pain, and a hard mass of the left breast. Echocardiography revealed a mass in the right atrium wall and interatrial septum, and massive pericardial effusion. ECG showed atrioventoricular block. We promptly performed a needle biopsy of the breast mass, which showed CD5-positive DLBCL, non-GCB type. The serum HIV reaction was negative. We thus diagnosed this patient as having cardiac and breast CD5-positive DLBCL, stage IVA, based on the massive pericardial effusion. The patient's prognosis was apparently poor. Therefore, she received 3 cycles of R-CHOP chemotherapy followed by autologous peripheral blood stem cell transplantation (PBSCT), resulting in a complete response. In general, cardiac lymphoma is associated with high mortality and has a poor prognosis. This case demonstrates that rapid and appropriate diagnosis, and immediate intensive chemotherapy followed by PBSCT might be necessary for the treatment of extranodal lymphoma indicative of a poor prognosis.