Simultaneous Development of Lymphoplasmacytic Lymphoma and Diffuse Large B-cell Lymphoma--analyses of the Clonal Relatedness by Sequencing CDR3 in Immunoglobulin Heavy Chain Genes

A 75-yr-old male simultaneously having lymphoplasmacytic lymphoma (LPL) and diffuse large B-cell lymphoma (DLBCL) is presented. He had manifested with lumbago, high-grade fever, and confusion. Physical examination on admission showed disorientation and severe back pain. There were neither lymphadenopathy nor hepatosplenomegaly. Routine laboratory tests showed moderate pancytopenia, hypercalcemia (serum calcium, 15.9 mg/dL), IgM lambda-type monoclonal gammopathy (IgG, 405 mg/dL; IgA, 42 mg/dL; and IgM, 2023 mg/dL), and lambda-type Bence-Jones protein in the urine (0.8 g/d). Bone marrow biopsy showed the clusters of surface lambda-positive small-sized mature-appearing lymphoplasmacytoid cells. Bone survey and computed tomographic scan showed multiple osteolytic lesions and a tumor involving the third lumbar spine (L3). An open biopsy of the L3 tumor showed diffuse proliferation of CD20- and lambda-positive large cells. We thus diagnosed the patient as simultaneously having LPL and DLBCL. Although the combination chemotherapy was at least partially effective, he died of bacteremia and organ failure after three courses of chemotherapy. To clarify the clonal relatedness between LPL and DLBCL, we analyzed the sequences of the complementarity-determining region 3 in immunoglobulin heavy-chain genes. The data showed that LPL and DLBCL in the present patient originated from two independent clones.