Standardized reporting of monoclonal immunoglobulin–associated renal diseases: recommendations from a Mayo Clinic/Renal Pathology Society Working Group

The term monoclonal gammopathy refers to the overproduction of a monoclonal Ig (MIg) that is detectable in the serum, urine, or tissue resulting from the clonal proliferation of Ig-producing plasma cells or B lymphocytes.1 The term monoclonal gammopathy of undetermined significance (MGUS) is applied when a MIg is detected in the absence of plasma cell or lymphoid malignancy or end organ damage, and it implies a "benign" condition.1,2