Multiple myeloma is a malignancy of plasma cells, which are mature B cells that produce antibodies. Histologically, bone marrow biopsies from patients with multiple myeloma show an increased number of plasma cells, often with abnormal forms such as binucleated or multinucleated cells. These cells may produce a monoclonal immunoglobulin, detectable as an M-protein spike in serum protein electrophoresis. Bone lesions are another hallmark and can be detected via radiographic imaging.
