[Complete response achieved after rituximab plus CHOP therapy in a patient with rapidly progressing Waldenstrom's macroglobulinemia].

A 62-year-old man presented with lymphocytosis, anemia, thrombocytopenia, abdominal lymphadenopathies, and gross splenomegaly. He had a high serum immunoglobulin M (IgM) of 1,150 mg/dl and IgM-kappa type monoclonal protein was detected. Bone marrow examination demonstrated massive infiltration of CD19+CD20+CD5-CD10-CD23-lymphoplasmacytic cells, and the diagnosis of Waldenstrom's macroglobulinemia (WM) was made. The serum levels of soluble interleukin-2 receptor and beta2-microglobulin were also elevated to 14,300 U/ml and 6.2 mg/l, respectively. The high tumor burden and aggressive clinical features prompted the initiation of CHOP therapy. After three courses of CHOP, the patient recovered from anemia and the serum IgM level decreased to 615 mg/dl. Then we administered rituximab in combination with CHOP (R-CHOP therapy). After an additional five courses of R-CHOP, bone marrow tumor cells, splenomegaly and lymphadenopathies entirely disappeared and IgM-type monoclonal protein also became negative on immunofixation studies. Thus, a complete response (CR) was achieved and the patient has remained in CR for 12 months. Although new therapeutic options for WM including combination chemotherapy have recently been explored, complete response rates defined by immunofixation remain low. Our case indicates that R-CHOP therapy is fully effective and tolerable for aggressive type WM.