[Serum paraprotein in a patient with chronic lymphatic leukemia].

We report a case of chronic lymphocytic leukemia associated with paraproteinemia which proved to be a complete immunoglobulin IgM lambda. This case is reported because the process of cellular differentiation exposed to intrinsic or extrinsic stimulation may undergo morphofunctional variations which lead to the formation of plasma cells with extremely high secretionary capacities during the course of chronic lymphocytic leukemia.