Translocations of MYC, bcl-2 and bcl-6 genes and Epstein-Barr virus infection in primary cardiac large B-cell lymphoma

Abstract

Objective: To investigate the translocations of MYC, bcl-2 and bcl-6 genes, the Epstein-Barr virus (EBV) status and the clinicopathological features of primary cardiac large B cell lymphoma (LBCL). Methods: Seven cases of primary cardiac LBCL were collected at Beijing Friendship Hospital, Capital Medical University, China from February 2013 to May 2019. The clinical feature, pathological morphology and immunophenotype were analyzed. The detections of EBV and gene rearrangements of MYC, bcl-2 and bcl-6 were conducted. The 2017 WHO classification of tumors of haematopoietic and lymphoid tissues was used to classify the tumors. Results: Four patients with right atrial lesions showed diffuse infiltration of medium size lymphoid cells with small vascular hyperplasia, without evidence of EBV infection. Without detectable gene rearrangements of MYC and bcl-2, 2 of the patients showed bcl-6 gene break-apart. The diagnosis was revised from diffuse LBCL to high-grade B-cell lymphoma, not otherwise specified (HGBL-NOS). There was a case of CD5+ diffuse LBCL involving the right atrium and ventricle and 2 cases of fibrin-associated diffuse LBCL located at left atrium without gene rearrangements of MYC, bcl-2 and bcl-6. However, EBER and EBNA2 were highly expressed in fibrin-associated diffuse LBCL. The patients were followed up for 10-71 months. Four cases of HGBL-NOS and a case of CD5+ diffuse LBCL received R-CHOP with/without autologous stem cell transplantation. All but two patients survived. Two cases of fibrin-associated diffuse LBCL were disease free without adjuvant chemotherapy and radiotherapy. Conclusions: Primary cardiac LBCL is heterogeneous, including at least HGBL-NOS. Primary cardiac HGBL-NOS most frequently occurs in the right atrium. Tumor cells of primary cardiac LBCL have the morphological characteristics similar to Burkitt lymphoma, lacking MYC and bcl-2 gene rearrangements, but usually show bcl-6 gene disruption. Fibrin-associated diffuse LBCL has a good prognosis and postoperative chemotherapy seems unnecessary.