LAUSR

A 47-year-old Japanese woman experienced a painless subcutaneous abdominal tumor. There was no significant medical history or other physical findings. FDG-PET showed multiple accumulation of FDG in femur and abdomen (Fig. 1), but no FDG uptake in bone. Histological examination of tumor revealed a neoplastic proliferation of differentiated plasma cells (Fig. 2a). Immunochemistry studies showed the cells to be positive to IgM (Fig. 2b), CD19, CD20, CD138, kappa immunoglobulin light chain CD138 and BCL2, but negative to IgG and CD3. Clonal immunoglobulin heavy chain gene rearrangements and BCL6 rearrangements were detected by southern blotting analysis and FISH, respectively. Peripheral blood and bone marrow examination demonstrated no clonal plasmacytosis. These findings suggested a diagnosis of primary cutaneous plasmacytoma. After three cycles of chemotherapy consisting of bortezomib cyclophosphamide, and dexamethasone, multiple masses disappeared. Extramedullary plasmacytoma is a plasma cell tumor that develops outside the bone marrow and may arise in the upper respiratory tract, gastrointestinal tract, and nervous