Primary plasma cell leukemia with extensive dense osteosclerosis: complete remission following combination chemotherapy

Diffuse osteosclerotic myeloma is very rare, and primary plasma cell leukemia with extensive osteosclerosis is even more rare. We describe a 71-year-old man who presented with severe anemia and dense widespread osteosclerosis similar to the X-ray finding of myelosclerosis. His peripheral blood showed 40% plasma cells. Bone marrow examination revealed heavy plasma cell infiltration with marked myelofibrosis and myelosclerosis. Protein electrophoresis and immunoelectrophoresis demonstrated an M-protein of IgG-lambda type. He was treated with cyclophosphamide, vincristine, and prednisolone for 10 months. A complete remission was obtained, with disappearance of M-protein and circulating plasma cells and normalization of complete blood counts, bone marrow picture, and biochemical parameters, as well as complete regression of myelofibrosis and osteosclerotic lesions. Unmaintained complete remission lasted for more than 1 year and he survived for more than 22 months. Our case indicated that one must include in the differential diagnosis of an osteosclerotic lesion the possibility of multiple myeloma, and that combination chemotherapy can induce a complete remission in this disease.