[Nonsecretory primary plasma cell leukemia successfully treated with VAD and MP therapy]

A 78-year-old woman was admitted to our hospital because of lumbago and appetite loss. Blood analysis revealed anemia, hypercalcemia and circulating plasma cells. Bone marrow aspiration showed an elevated ratio (43%) of plasma cells, which expressed CD38 in the absence of CD19 and CD56 expression. Spinal MR imaging revealed multiple compression fractures and suggested diffuse invasion of plasma cells into the spinal bodies. No M-protein was detectable in serum or urine by immunoelectrophoresis and immunofixation, but cytoplasmic M-protein (IgG-kappa) was detected by enzyme antibody staining. On the basis of the history and data, nonsecretory primary plasma cell leukemia was diagnosed. First, the patient was given modified VAD therapy (vincristine, doxorubicin, and prednisolone) and complete remission was obtained. Then MP therapy (melphalan and prednisolone) was instituted, and remission has since been maintained for 11 months. Like many other cases of primary plasma cell leukemia, this case suggests that CD56 may act as an adhesion molecule between neoplastic plasma cells and bone marrow stromal cells. Our experience with this exceedingly rare case suggests the superiority of combination chemotherapy as an induction therapy and the effectiveness of MP therapy as maintenance therapy for this disease.