Primary Cardiac Diffuse Large B-Cell Lymphoma: A Diagnostic Pitfall With Overlapping Imaging Features.

BACKGROUND

Primary cardiac lymphoma (PCL) is an exceptionally rare cardiac malignancy with heterogeneous presentations and variable multimodality imaging features.

CASE SUMMARY: A 60-year-old man presented with heart failure and complete atrioventricular block. Echocardiography revealed a massive infiltrative right atrial mass with pericardial effusion. The mass demonstrated malignant features on cross-sectional imaging. As biopsy was considered high risk and a definitive pathologic diagnosis was lacking, radiotherapy was initiated in the setting of a structural oncologic emergency to maintain clinical stability, and extracardiac biopsy ultimately established primary cardiac diffuse large B-cell lymphoma. The patient received dose-adjusted R-EPOCH chemotherapy, achieving complete metabolic response after 3 cycles.

DISCUSSION: PCL and cardiac angiosarcoma can share overlapping imaging features that may delay diagnosis; early histopathological confirmation is pivotal to guide therapy. In selected cases, radiotherapy can provide temporary stabilization until tissue diagnosis is established.

TAKE-HOME MESSAGE: PCL requires individualized management in the absence of established guidelines.