Dr. Christine I. Chen, MD, FRCPC
Princess Margaret Hospital,
University Health Network,
Multiple myeloma arises from a malignancy of plasma cells in the bone marrow which typically produce an immunoglobulin, also referred to as a monoclonal protein (M-protein), that is detectable in the patient's blood and/or urine. Myeloma is not a common disease (incidence of 1400/year in Canada), typically affecting older individuals (median age 65 years). It is more common in blacks and slightly more prevalent in males. Since myeloma is a relatively slow-growing malignancy, many patients will have the disease for months or even years before a diagnosis is made and may continue to follow an indolent course. The pathogenesis of the disease is poorly understood.
Characteristic clinical features of multiple myeloma are anemia, renal failure, bony lesions with pathologic fractures and associated pain, hypercalcemia, and recurrent infections (See Table 1). Many patients, however, will present with asymptomatic anemia or a monoclonal gammopathy, which is usually discovered during incidental lab testing.