This neoplasm is not reportable.


IgM monoclonal gammopathy of undetermined significance

ICD-O-3 Morphology

9761/1: IgM monoclonal gammopathy of undetermined significance
Effective 2021 and later


This neoplasm is not reportable

Primary Site(s)

No primary site specified
This neoplasm is reportable for primary sites C700-C729, C751-C753 only.

Abstractor Notes

Patients with IgM MGUS lack the signs and symptoms of an overt lymphoproliferative disorder of plasma cell neoplasm, and the paraprotein is typically discovered incidentally on serum protein electrophoresis.

Alternate Names



IgM monoclonal gammopathy of undetermined significance (MGUS) is defined by a serum IgM paraprotein concentration < 30 gram per liter; bone marrow lymphoplasmacytic infiltration of < 10%; and no evidence of anemia, constitutional symptoms, hyperviscosity, lymphadenopathy, hepatosplenomegaly, or other end-organ damage that can be attributed to the underlying lymphoproliferative disorder.

IgM MGUS is a precursor condition that may progress to overt lymphoma, lymphoplasmacytic lymphoma (LPL), Waldenstrom macroglobulinemia, or primary amyloidosis.

Corresponding ICD-9 Codes

273.1 Monoclonal paraproteinemia

Corresponding ICD-10 Codes

D47.2 Monoclonal gammopathy

Corresponding ICD-10-CM Codes (U.S. only)

D47.2 Monoclonal gammopathy (effective October 01, 2015)


Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J (Eds):
WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues (Revised 4th edition)
IARC: Lyon 2017
Section: Mature B-cell neoplasms
Pages: 236

National Cancer Institute
Section: General Information About Plasma Cell Neoplasms

International Classification of Diseases for Oncology, Third Edition, Second Revision. Geneva: World Health Organization, 2020
Section: ICD-O-3.2 (2020) Morphological Codes