Diagnostic Studies. The results of most staging studies are the same as for other malignant primary tumors. On bone scans, however, myelomas may not appear as abnormal (cold lesions). Laboratory findings include anemia, hyperuricemia, and hypercalcemia. A serum protein electrophoresis (SPEP) or urine protein electrophoresis (UPEP) usually reveals a monoclonal gammopathy.

Histologic features include aggregates of immature plasma cells with little intervening stroma. The neoplastic plasma cells are hyperchromatic, and the clumps of chromatin give the cell a “clock face” or “spoke wheel” appearance.

Treatment/Prognosis. Myeloma is very sensitive to radiation therapy, and reossification of the tumors often occurs within several months. Large tumors or involvement of high-stress areas necessitate surgical stabilization for fracture prophylaxis; however, myeloma is one of the few malignant bone lesions that can heal, at least in the humerus, even after pathologic fracture (see Plate 6-30). When the disease is disseminated, chemotherapy and even bone marrow transplant may be indicated.