What is Multiple myeloma?

An uncommon disease that occurs more frequently in men than in women and is associated with anemia, hemorrhage, recurrent infections, and weakness. Ordinarily, it is regarded as a malignant neoplasm that originates in bone marrow and involves chiefly the skeleton, with clinical features attributable to the sites of involvement and to abnormalities in formation of plasma protein; characterized by numerous diffuse foci or nodular accumulations of abnormal or malignant plasma cells in the marrow of various bones (especially the skull), causing palpable swellings of the bones, and occasionally in extraskeletal sites; radiologically, the bone lesions have a characteristic punched-out appearance. The myeloma cells produce abnormal proteins in the serum and urine; those formed in any one example of multiple myeloma are different from other myeloma proteins, as well as from normal serum proteins, the most frequent abnormalities in the metabolism of protein being: 1) the occurrence of Bence Jones proteinuria, 2) a great increase in monoclonal γ-globulin in the plasma, 3) the occasional formation of cryoglobulin, and 4) a form of primary amyloidosis. The Bence Jones protein is not a derivative of abnormal serum protein, but seems to be formed de novo from amino acid precursors.