RT Book, Section A1 Lichtman, Marshall A. A1 Kaushansky, Kenneth A1 Prchal, Josef T. A1 Levi, Marcel M. A1 Burns, Linda J. A1 Armitage, James O. SR Print(0) ID 1133365287 T1 Essential Monoclonal Gammopathy T2 Williams Manual of Hematology, 9e YR 2017 FD 2017 PB McGraw-Hill Education PP New York, NY SN 9781259642470 LK hemonc.mhmedical.com/content.aspx?aid=1133365287 RD 2024/03/28 AB Essential monoclonal gammopathy is the presence of a serum monoclonal immunoglobulin (Ig) or a serum and urine monoclonal immunoglobulin light chain in the absence of evidence for a B-cell tumor (eg, B-cell lymphoma, macroglobulinemia, myeloma, plasmacytoma, amyloidosis) over a period of observation.The monoclonal immunoglobulin may be of any isotype and may occasionally be of multiple isotypes (see Table 67–1).Synonyms for essential monoclonal gammopathy include (1) monoclonal gammopathy; (2) benign monoclonal gammopathy; and (3) monoclonal gammopathy of unknown significance, with the acronym MGUS. The latter seems less appropriate now that the significance of this diagnosis is precisely known, and it is one of many examples of nonprogressive, clonal disorders with a predisposition to undergo clonal evolution to a malignant disorder (eg, adenomatous colonic polyp), making its significance apparent.