What is MGUS? – Pathosomes

MGUS is monoclonal gammopathy of unknown significance. MGUS involves the production of M-protein by benign plasma cells.

What is the Pathology of MGUS?

The pathology of MGUS is:

-Etiology: The cause of MGUS is not known. Infection, immune system issues, and the environment may play a role.

-Genes involved: DCC gene.

-Pathogenesis: The sequence of events that lead to MGUS come from clonal plasma cells in the bone marrow. These cells harbor somatic hypermutation of the variable regions and are class-switched.

-Histology: The histology associated with MGUS shows bone marrow <10% plasma cells.

Normal Serum Protein Electrophoresis. Right-hand position for serum protein electrophoresis mnemonics. Visual mnemonics for serum protein electrophoresis. Medina-De la Garza CE, García-Hernández M, de Los Ángeles Castro-Corona M - Medical education online (2013). Not altered. CC.
MGUS. a: Densitometry tracing of gel electrophoresis of normal serum.b: Densitometric tracing of gel electrophoresis of subject with monoclonal band. Prevalence and type of monoclonal gammopathy of undetermined significance in an apparently healthy Nigerian population: a cross sectional study. Onwah AL, Adeyemo TA, Adediran A, Ajibola SO, Akanmu AS - BMC blood disorders (2012). Not altered. CC.
MGUS. Serum immunofixation electrophoresis of subject shows two monoclonal bands: IgA kappa (in β2 position) and IgG lambda (in mid-γ region). Prevalence and type of monoclonal gammopathy of undetermined significance in an apparently healthy Nigerian population: a cross sectional study. Onwah AL, Adeyemo TA, Adediran A, Ajibola SO, Akanmu AS - BMC blood disorders (2012). Not altered. CC.
MGUS SPEP. Serum protein electrophoretic patterns on an Agarose gel showing subject’s β band appearing dense and a discrete band in the γ region. This is shown with the arrows. Prevalence and type of monoclonal gammopathy of undetermined significance in an apparently healthy Nigerian population: a cross sectional study. Onwah AL, Adeyemo TA, Adediran A, Ajibola SO, Akanmu AS - BMC blood disorders (2012).

How does MGUS Present?

Patients with MGUS are more often male than female, and this condition is more common among the elderly population. The symptoms, features, and clinical findings associated with MGUS include bone pain, fatigue or weakness, unintentional weight loss, fever or night sweats, peripheral neuropathy, enhanced bone loss and fractures.

How is MGUS Diagnosed?

MGUS is diagnosed by blood and urine screening of abnormal proteins with a lab test called serum protein electrophoresis and/or serum immunofixation.

How is MGUS Treated?

No treatment is recommended for patients with MGUS. Long-term follow-up is generally advised.

What is the Prognosis of MGUS?

The prognosis of MGUS is good. The annual risk of progression from MGUS to multiple myeloma (MM), Waldenström macroglobulinemia (WM), amyloidosis (AL), or other lymphoproliferative disorders is approximately 1%. However, the mode and risk of progression vary between IgM MGUS and those with non-IgM MGUS.