monoclonal gammopathy
nounMedical Definition of monoclonal gammopathy
: any of various disorders marked by proliferation of a single clone of antibody-producing lymphoid cells resulting in an abnormal increase of a monoclonal antibody in the blood serum and urine and that include both benign or asymptomatic conditions and neoplastic conditions (as multiple myeloma and Waldenström's macroglobulinemia)
— called also plasma cell dyscrasia
— see m protein sense 2