Multiple bone lesions and hypercalcemia presented in diffuse large B cell lymphoma: mimicking multiple myeloma?

We encountered a 58-year-old female patient who developed hypercalcemia and multiple bone lesions. She complained of lumbodorsal pain, nausea and vomiting on admission. Radiographic examination revealed multiple osteolytic lesions. She was diagnosed diffuse large B cell lymphoma (BLBCL) by bone marrow examination and biopsy of cervical lymph node. She underwent eight cycles of chemotherapy and is now in the stable stage. Osteogenic potential of mesenchymal stem cells from bone marrow was found to be correlated with the expression of Dickkopf1 (DKK-1) in the bone marrow plasma and lymphoma cells before and after treatment. PTH-related protein (PTHrP) expression was detectable in the lymphoma cells and was elevated in the serum. The receptor activator of nuclear factor κB ligand expression was found to be elevated in the bone marrow plasma and mesenchymal stem cells. These findings suggest that factors affecting the differentiation of both osteoblasts and osteoclasts involved in the pathogenesis of hypercalcemia and bone lesions of lymphoma. This was similar to that of multiple myeloma in which bone lesions and hypercalcemia are frequently observed.