[Malignant transformation of monoclonal gammopathy of undetermined significance].

Monoclonal gammopathy of undetermined significance (MGUS) is found in approximately 3% of the general population aged 50 years or older. MGUS is a premalignant state. The risk of malignant transformation is about 1% per year. Some factors predictive of malignant transformation have been identified: type of serum monoclonal protein, monoclonal protein value, bone marrow plasmocytosis and serum free light chain ratio. Predictive scores combining these factors have recently been proposed and make it possible to identify groups of patients with significantly different rates of transformation. These scores require validation. These scores will probably allow individualization of management and monitoring.