Primary cardiac lymphoma is a rare type of extranodal lymphoma that involves only heart and/or pericardium. It is usually observed in immunodeficient people. However, immunocompetent patients may also suffer from this disease. Most primary cardiac lymphomas are of B-cell lineage, and they usually present as diffuse large B-cell lymphoma (DLBCL). Diffuse large B-cell lymphoma with concurrently high MYC and BCL2 expression, which is named as double-expressor lymphoma (DEL), is a rare subtype of DLBCL. Here we report a rare case of a primary cardiac DEL in an immunocompetent 65-year old Chinese woman. Echocardiography and magnetic resonance imaging revealed a mass of 6.6 cm×5.6 cm in the right atrium. No tumor formations were observed in other organs. Histopathologic examination showed that the cardiac tumor was diffuse large B-cell lymphoma, non-germinal center B-cell type by Hans algorithm. The tumor cells showed high MYC and BCL2 protein expression by immunohistochemistry, with high proliferative index. Copyright © 2017 Elsevier Inc. All rights reserved.