hematology and oncology
Multiple Myeloma
Key Points
Malignant plasma cells produce monoclonal immunoglobulin and invade and destroy bone. Expanding plasmacytomas and cytokine secretion cause multiple, discrete, osteolytic lesions (usually in the pelvis, spine, ribs, and skull) and diffuse osteoporosis; pain, fractures, and hypercalcemia are common. Anemia and renal failure are common. Amyloidosis develops in about 10%, typically patients who produce excess lambda light chains. Do serum and urine protein electrophoresis followed by immunofixation, quantitative immunoglobulins, and measurement of serum free light chains. Do bone marrow aspiration and biopsy. Symptomatic patients and those with organ dysfunction should be treated with drug therapy, which may include corticosteroids, chemotherapy drugs, proteasome inhibitors, immunomodulatory agents, monoclonal antibodies, selective inhibitors of nuclear export, histone deacetylase inhibitors, and cellular and antibody-based immune therapies targeting B-cell maturation antigen. Stem cell transplantation is an option for some patients, but newer, highly effective treatment options may make it unnecessary in others. 