Synchronous diffuse large B-cell lymphoma and malignant clonal plasma cells in bone marrow as primary presentation: a diagnostic and therapeutic challenge.

Coexistence of Diffuse Large B-Cell Lymphoma (DLBCL) with other morphologically and phenotypically distinct lymphoid neoplasm although unusual, has been reported in literature. The most common lymphoid neoplasms associated with DLBCL are Hodgkin's lymphoma, mantle cell lymphoma and marginal zone lymphoma. However, they have been reported predominantly in the sites other than the bone marrow. Rarely, DLBCL associated with paraproteinemia of IgM type, result of monoclonal plasma cell proliferation, has also been reported in literature. There is either an associated increase in the free light chain levels or disruption in the normal kappa: lambda ratio. However, co-existence of DLBCL with malignant non secretory clonal plasma cells, diagnosed primarily in the bone marrow has not been reported in the literature.