Multiple myeloma: clinical features and indications for therapy.

Multiple myeloma is a malignant plasma-cell proliferative disease with an expected 15,270 new cases and 11,070 deaths in the USA in 2004 alone. This accounts for 1% of all malignancies and slightly more than 10% of all hematologic malignancies in Caucasians and 20% in African Americans. The diagnosis is based on the presence of bone pain, anemia, and plasma-cell infiltrate in the bone marrow or within bone lesions. It is essential that the spectrum of plasma-cell proliferative disorders be recognized: monoclonal gammopathy of undetermined significance (MGUS), smoldering (asymptomatic) multiple myeloma (SMM), and active (symptomatic) MM. These distinctions affect important management decisions. Other related disorders include primary systemic amyloidosis, POEMS syndrome, and acquired Fanconi syndrome.