Monoclonal gammopathy of undetermined significance

Asymptomatic, usually slowly progressive

Occurring in apparently healthy people or in those with other conditions

Associated with B-cell cancers but also nonlymphoreticular tumors

B-cell lymphoma, chronic lymphocytic leukemia, multiple myeloma, or, less commonly, carcinomas of the breasts, biliary tree, gastrointestinal tract, kidneys, and prostate

Associated with chronic inflammatory and infectious conditions

Chronic cholecystitis, osteomyelitis, pyelonephritis, rheumatoid arthritis, tuberculosis

Associated with various other disorders

Familial hypercholesterolemia, Gaucher disease, Kaposi sarcoma, lichen myxedematosus, liver disorders, myasthenia gravis, pernicious anemia, hyperthyroidism

Malignant plasma cell disorders

Asymptomatic, progressive

Usually intact monoclonal immunoglobulin molecules (IgG, IgA, IgM, IgD) with or without monoclonal light chains (Bence Jones proteins) in urine and/or in serum)

Smoldering multiple myeloma

Symptomatic, progressive

Excess production of IgM

Macroglobulinemia

Most often IgG, IgA, or light chains (Bence Jones) only

Multiple myeloma

Usually intact immunoglobulin molecules (IgG, IgA, IgM, IgD) with or without monoclonal light chains (Bence Jones proteins) in urine and/or serum)

Nonhereditary primary systemic amyloidosis

Heavy chains

IgG heavy chain disease (sometimes benign)

IgA heavy chain disease

IgM heavy chain disease

IgD heavy chain disease

Transient plasma cell disorders

Not necessarily symptomatic

Associated with drug hypersensitivity, viral infections, and heart or transplant surgery