Monoclonal gammopathy of undetermined significance.
Monoclonal gammopathy of undetermined significance (MGUS) accounted for 56% of the 1026 patients with a monoclonal plasma cell disorder seen at the Mayo Clinic during 1992. Approximately 3% of persons older than 70 years and 1% of those older than 50 years had MGUS. In a series of 241 Mayo Clinic patients with a serum M-protein but no evidence of multiple myeloma, macroglobulinemia, primary amyloidosis, lymphoma, or related disorders, followed up for 20 to 35 years (median, 22 years), the condition of 19% remained stable. Ten percent had an increase in the serum M-protein to 3.0 g/dL or more but did not require chemotherapy, whereas 47% died of unrelated causes. 59 of the 241 patients (24.5%) developed a serious disease during the median follow-up period of 22 years: multiple myeloma in 39 patients, primary amyloidosis in 8, Waldenström's macroglobulinemia in 7, and other malignant lymphoproliferative disorders in 5. The actuarial rate of malignant transformation was 17% at 10 years and 33% at 20 years. The median interval from diagnosis of MGUS to the diagnosis of serious disease was 8.5 to 10.5 years. No single factor can differentiate a patient with benign monoclonal gammopathy from one in whom a malignant plasma cell disorder will subsequently develop. Therefore, the serum M-protein must be measured and a clinical evaluation conducted periodically.
Kyle
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Division of Hematology and Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905.
D000206:Actuarial Analysis; D000368:Aged; D000686:Amyloidosis / Q000453:epidemiology; D001536:Bence Jones Protein / Q000652:urine; D015897:Comorbidity; D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D008998:Monoclonal Gammopathy of Undetermined Significance / Q000097:blood / Q000453:epidemiology*; D009101:Multiple Myeloma / Q000453:epidemiology; D010266:Paraproteins / Q000032:analysis; D011230:Precancerous Conditions / Q000453:epidemiology; D011507:Proteinuria / Q000209:etiology; D008258:Waldenstrom Macroglobulinemia / Q000453:epidemiology
D010266:Paraproteins; D001536:Bence Jones Protein