Part 2: Multiple Myeloma
Todd Zimmerman, MD
Dr. Zimmerman is an associate professor of medicine, Section of Hematology/Oncology, University of Chicago, Chicago, IL.
Question 5
A 73-year-old woman with a history of rheumatoid arthritis presents to the emergency department with new left arm pain. Plain radiographs reveal a large lytic lesion in the left humerus. A skeletal survey reveals additional lytic lesions. She has stable anemia (hemoglobin, 10.1 g/dL) and stable renal insufficiency (serum creatinine, 1.6 mg/dL). Serum protein and urine electrophoresis and immunofixation reveal no evidence of a monoclonal protein; however, polyclonal immunoglobulins are surpressed. On serum free light chain assay testing, the kappa/lambda ratio is also suppressed at 0.01. A biopsy of the humeral lesion reveals lambda light chain–restricted malignant plasma cells. A bone marrow biopsy reveals lambda light chain–restricted plasma cells accounting for 60% of the cellular marrow. Which of the following tests can best assess this patient’s response to therapy?
