Monoclonal Gammopathy of Undetermined Significance (MGUS)

MGUS is a benign condition that can lead to multiple myeloma. Approximately 1.5% of persons older than 50 years and 3% of the population older than 70 in the U.S. are living with MGUS. It involves an excess of M protein, but the plasma cells have not formed a tumor or multiple lesions, no symptoms have occurred, and other criteria for a myeloma diagnosis are absent. MGUS itself is benign, but over many years, approximately 16% of individuals with MGUS will progress to a malignant plasma cell disorder, such as multiple myeloma.

Characteristics:

    • Serum M protein level is < 3 g/dL (less than 3 grams per deciliter)
    • Percentage of plasma cells in the bone marrow is < 10%
    • Absence of anemia, renal failure, hypercalcemia, and ostolytic lesions