Snapshot A 65-year-old man presents with generalized "pain in his bones," and a recent fracture that occurred while he was walking. He has also had multiple infections recently. Recent lab work demonstrated hypercalcemia, an increased β2 microglobulin, an increase BUN and Cr as well as a peripheral smear that demonstrated an abnormal stacking of RBC's. Introduction Multiple myeloma is cancer of monoclonal plasma cells produces large amounts of IgG (55% of cases) or IgA (25% of cases) Epidemiology most common primary tumor of the bone/ bone marrow in patients > 50 years of age Presentation Symptoms bone pain back pain can be the presenting symptom sequelae associated with hypercalcemia sequelae associated with renal failure Evaluation Serum protein electrophoresis monoclonal immunoglobulin spike (M protein) Urinalysis Ig light chains (Bence Jones protein) Peripheral blood smear RBC rouleaux formation Igs coat RBC and neutralize the ionic charge than normally repells RBCs Bone marrow aspiration proliferation of large monoclonal plasma cells "fried-egg" appearance Serology hypercalcemia result of bone degradation due to cytokine production that activates RANKL receptor on osteoclasts prolonged bleeding time Imaging punched-out lytic bone lesions on radiograph Differential Waldenstrom's macroglobulinemia presentation generalized lymphadenopathy bleeding IgM disrupts platelet aggregation sequelae of blood hyperviscosity retinal hemorrhage stroke evalutation serum protein electrophoresis M spike = IgM unlike multiple myeloma which is IgA/G imaging no lytic bone lesions Monoclonal gammopathy of undetermined significance (MGUS) increased gamma globulin on serum electrophoresis but no symptoms of multiple myeloma are present can progress to MM (1% per year) Management Multiple myeloma is a disease of plasma cells (thus the treatments below) mephalan chemotherapy drug - nitrogen mustard alkylating steroids reduce many side effects associated with chemotherapy thalidomide, lenalidomide immunomodulatory agent bortezomib proteasome inhibitor bone marrow transplant definitive therapy, preferable in young patients Prognosis, Prevention, and Complications May lead to renal insufficiency ↑ susceptibility to infection anemia primary amyloidosis (AL) Poor prognosis high urine levels of β2 microglobulin suggest severe myelomatous cell burden β2 microglobulin can be used to track severity and response to treatment