Diffuse large B-cell non-Hodgkin's lymphoma and osteosclerotic myeloma with features of POEMS syndrome.

Multiple myeloma is a clonal hematopoietic neoplasm characterized by the proliferation of malignant plasma cells and associated end-organ damage, most notably lytic lesions in the bones. Osteosclerotic myeloma is an unusual variant of the disease in which the skeletal involvement is characterized by sclerotic lesions instead of classical lytic lesions. The disease can be associated with paraneoplastic symptoms, which have been given the acronym POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, M protein, skin changes). In addition to clonal plasma cell dyscrasias, some cases of POEMS syndrome are associated with Castleman's disease, and in 11% to 30% of the cases both Castleman's disease and clonal plasma cell proliferation are present. POEMS syndrome has rarely been described in patients with non-Hodgkin's lymphoma.