266 - Multiple Myeloma Flashcards
What is the therapy for myeloma?
High dose combination therapy with autologous stem cell transplant
- Prognosis variable*
- Do more chemo if pt not elligible for stem cell transplant*
What is the significance of Ig light chains in multiple myeloma?
Myeloma cells produce more light chain than heavy chain
-> extra light chains floating around
- Excreted in urine as Bence-Jones proteins
- Can be nephrotoxic
- Misfolded light chains -> amyloid
- -> Nephrotic syndrome
What is the normal kappa:lamba ratio in plasma cells?
What is the significance of a deviation from this ratio?
Kappa:Lambda = 2:1
Deviation => Clonal population (possible malignancy, cannot diagnosis without consistent clinical features)
- Note: Dr. Gao’s lecutre (264) says ~1:1, and Dr. Wolniak’s lecture (266) says ~2:1*
- Wikipedia says normal is 0.26 - 1.65 so pick your poison here I guess!*
What hematologic malignancy arises from plasma cells?
Multiple myeloma
What cytokine drives myeloma cell growth, survival, and Ig production?
IL-6
What is the most frequent cause of death in multiple myeloma?
Infection
Malignant plasma cells
- > no healthy/functional plasma cells
- > not enough working antibody
- > cannot protect against infection
What testing method do we use to find monoclonal gammopathies?
SPEP or UPEP
- If <10% clonal plasma cells = monoclonal gammopathy of undetermined significance (MGUS)*
- If >10% clonal plasma cells = may be multiple myeloma (need to have consistent clinical features though)*
What are the characteristics of plasma cells?
(2 morphologic features, 2 markers)
- Fried egg appearance
- Clock-face chromatin
- CD38+
- CD138+
Markers are cytoplasmic => detected on immunostain, not flow
What do plasma cells produce in abundance that can have pathologic effects on organs (especially the kidney)?
Immunoglobulins (antibodies) -> deposition -> tissue damage
Ig Light chains can also form amyloid -> tissue damage
What finding on peripheral blood smear may be concerning for multiple myeloma?
Roleaux formation (stack of coins)
- Immunoglobulins in serum alter normal (-) charge of RBCs -> they stick together
- Not specific, but warrants further screening*
What is the diagnosis if a patient has 10-60% monotypic plasma cells but no clinical signs of myeloma?
Smoldering myeloma (<20%)
75% chance of turning into myeloma
What will plasma cells look like on flow cytometry?
CD 19+
CD56-
If CD19- and CD56+, likely a neoplastic plasma cell
Immunostain will show CD138+, CD38+ (but cytoplasmic)
What are the diagnostic criteria for multiple myeloma?
≥ 10% clonal plasma cells in the bone marrow, in the setting of myeloma-defining clinical criteria
- Myeloma-defining criteria
- Hypercalcemia
- Renal insufficiency
- Anemia
- Bone lesions
Monoclonal gammopathy is not sufficient to diagnose - need clinical criteria
What do Bence Jones protiens in the urine indicate?
Multiple myeloma
If consistent clinical picture (ex: lytic bone lesions, hypercalcemia)
Ig Light Chains enter the urine -> Bence Jones proteins
