Clinicopathological analysis of a composite lymphoma containing both T- and B-cell lymphomas

Composite lymphomas (CLs) have been reported in 1-4.7% of all lymphomas, however, CLs containing both T- and B-cell lymphomas (CTBLs) are very rare. Here, we examined the clinical and pathological features of 29 CTBLs. These CTBLs included 21 patients with angioimmunoblastic T-cell lymphoma (AITL) and diffuse large B-cell lymphoma (DLBCL), two with adult T-cell leukemia/lymphoma and DLBCL, one with AITL and Follicular lymphoma, one with Lennert lymphoma and DLBCL, one with subcutaneous panniculitis-like T-cell lymphoma and DLBCL, one with peripheral T-cell lymphoma (PTCL) and DLBCL, one with cutaneous T-cell lymphoma and DLBCL, and one with PTCL and chronic lymphocytic leukemia. Eighteen of 27 patients (67%) were shown to be Epstein-Barr virus (EBV)-encoded RNA-positive in their B-cell lymphoma component. T-cell and B-cell clonality were confirmed by flow cytometry, Southern blot analysis, and/or polymerase chain reaction (PCR). Using Southern blot analysis, clonal immunoglobulin heavy chain (IgH) and T-cell receptor (TCR) rearrangements were detected in 11 of 21 and 15 of 24 cases, respectively. Using PCR analysis, clonal IgH and TCR rearrangements were detected in 7 of 8 and 7 of 7 Southern blot-negative cases, respectively. Our results suggested that PCR analysis was useful in diagnosing CTBL.