With an obvious diagnosis, the differential diagnosis was easy to establish [1,2, 3], including: a) monoclonal gammapathy ofundetermined significance (MGUS) and b) smoldering myeloma, both with monoclonal immunoglobulin in the serum less than 3g/dl, >10% plasma cells in bone marrow, no evidence of myeloma end – organ damage – anemia, renal failure, hypercalcemia,lytic lesions; c) Waldenstrom's macroglobulinemia with IgM paraprotein peak and lymphoplasmacytic bone marrow infiltration[1]. This evidence concerns the gene CD40LG and plasma cell myeloma.