The evolution of asymptomatic monoclonal gammopathies. A follow-up of 20 cases over periods of 3-14 years.

Twenty cases of "asymptomatic" monoclonal gammopathies were detected by routine electrophoresis in patient's sera or in blood donors and were followed over 3-14 years. Four cases have shown a malignant evolution-two evolved toward Waldenström's macroglobulinemia after 3 years and two could be classified as myeloma 3 and 7 years, respectively, after detection of the monoclonal protein. The remaining cases were still "asymptomatic" 4 years later (7 cases), 7-9 years later (8 cases) and 14 years later (1 case). A malignant evolution occurred in approximately 20% of cases.