Monoclonal Gammopathy of Undetermined Significance Background MGUS stands for monoclonal gammopathy of undetermined significance. By definition, there can be no evidence of plasma cell myeloma, amyloidosis, lymphoma or leukemia, or any disorder that may cause a monoclonal gammopathy. The importance of this diagnosis lies in the risk of progressing to a malignancy such as multiple myeloma.
Patients are usually at an advanced age but there are no known disease associations.
Volume 9, Third Series.