Multiple myeloma

Alternative names:

malignant plasmacytoma; multiple plasmacytoma of bone; myelomatosis; plasma cell myeloma

Definition:

A cancer of the bone marrow composed of plasma cells.

Causes, incidence, and risk factors:

Multiple myeloma is characterized by the overgrowth and malfunction of plasma cells in the bone marrow. The growth of the plasma cells interferes with the growth of red blood cells, white blood cells and platelets; therefore anemia, susceptibility to infection, and tendencies toward bleeding develop. As the cells grow and expand in the bone marrow, they cause pain and destruction of the bones. If the bones in the spine are affected, compression of the nerves may result causing numbness or paralysis. Renal failure is a frequent complication caused by the excess calcium related to bone destruction. Multiple myeloma affects older adults. Other risk factors are unknown. This disease is rare with about 3 new cases per 100,000 people a year.