393 - Multiple Myeloma and Myelodysplastic Syndromes Flashcards
What does multiple myeloma look like histologically?
numerous plasma cells with a fried egg appearance, “clock face” chromatin, and intracytoplasmic inclusions containing Ig (in bone marrow)
What types of antibodies are produced in MM?
IgG (55%) or IgA (25%)
What is the most common primary tumor arising within the bones of the elderly?
multiple myeloma
What is found in the urine of patients with MM?
Bence Jones protein - Ig light chain
What is seen on x-ray in MM?
punched-out lytic bone lesions
What is seen in the blood smear of MM patients?
Rouleaux formation
What is seen in electrophoresis in MM?
M spike
What type of amyloidosis is associated with MM?
primary amyloidosis
Does MM increase susceptibility to infection?
yes
Differentiate the causes of M spike found in MM vs. Waldenstrom macrogobulinemia.
MM: IgG and/or IgA
WM: IgM
What blood and bone findings differentiate Waldenstrom macroglobulinemia from MM?
- IgM –> hyperviscosity symptoms
2. NO lytic bone lesions
What are the two main characteristics of MGUS?
- serum monoclonal protein < 3g/dL (M spike)
2. bone marrow with < 10% monoclonal plasma cells
How does MGUS relate to MM?
it is an asymptomatic precursor to MM; patients with MGUS develop MM at a rate of 1-2% per year
What are myelodysplastic syndromes?
Stem cell disorders involving ineffective hematopoiesis –> defects in cell maturation of all non-lymphoid lineages.
What causes MDS?
De novo mutations or environmental exposure (e.g. radiation, benzene, chemotherapy)
