Essentials of Diagnosis
M protein in the serum without symptoms or signs of multiple myeloma, macroglobulinemia, amyloidosis, or lymphoma.
Less than 10% plasma cells in the bone marrow.
The incidence of monoclonal gammopathy of uncertain significance (Monoclonal Gammopathy of Uncertain Significance ) increases with age and may approach 3% in persons 70 years of age or older. Lymphoid malignancies, amyloidosis, or multiple myeloma will develop in as many as one-third of patients with apparently benign monoclonal gammopathies. No specific therapy is necessary, but close observation is required. MGUS patients should be periodically monitored for changes in serum M proteins, urinary Bence-Jones proteins, evidence of renal failure, anemia, hypercalcemia, lytic bone lesions, or bone marrow plasmacytoses. Risk of developing a malignant disorder is 12% at 10 years, 25% at 20 years, and 30% at 25 years. Parameters that suggest a favorable prognosis include (1) concentrations of homogeneous immunoglobulin less than 2 g/dL, (2) no increase in concentration of the immunoglobulin from the time of diagnosis, (3) no decrease in the concentration of normal immunoglobulins, (4) absence of a homogeneous light chain in the urine, and (5) normal hematocrit and serum albumin.