Haematology 11 - Plasma cell myeloma and Monoclonal Gammopathy of Uncertain Significance Flashcards
What immunoglobin is produced by myeloma cells?
One single type (eith IgG or IgA) which is known as paraprotein or M spike
What are Bence Jones proteins?
Urine monoclonal free light chains
What is Waldenstrom’s-Lymphoplacytic lymphoma?
A lymphoplasmocytic lymphoma with IgM paraprotein that causes visual disturbances
and mucous lesions???
What is the name of the premalignant condition that ALWAYS precedes myeloma?
Monoclonal gammaopathy of uncertain significance (MGUS)
What is the difference between a pre-myeloma MGUS and pre-lymphoma MGUS?
Pre-myeloma: IgG/A-producing B cells
Pre-lymphoma: IgM-producing B cells
What are the two most significant risk factors for myeloma?
Obesity
Black > causasians/ asians
age is another risk factor
- chronic infection/ inflammation can increase the risk e.g. rheumatoid arthritis, viral (HHV8/HIV): immune system is more active whereby there is more active proliferation and differentiation of B cells, creating more of a chance for error.
What are the diagnostic criteria for MGUS?
Serum M-protein (i.e. paraprotein) <30g/L
BM clonal plasma cells <10%
Asymptomatic: no lytic lesions, no organ/tissue impairment, no clincal manifestation
no evidence of other B cell proliferation
**less severe version of multiple myeloma
What are the risk factor for progession of MGUS into multiple myeloma?
- non-IgG paraprotein (i.e. IgG is GOOD, G for Good!!)
- M spike (IgG/IgA paraprotein) >15
- abnromal serum free light chain ratio
average risk of progression to Multiple myeloma is 1%, so most people will not go on to develop multiple myeloma
What is smouldering myeloma?
Serum M-protein >30g/L
BM clonal plasma cells >10%
Asymptomatic- no signs of end organ damage
What is the clinical spectrum of multiple myeloma diseases?
Essentially MGUS is the least severe version
Then you have smouldering myeloma which is a more severe version but doesn’t have any organ damage
Then you have multiple myeloma
Diagnostic criteria of multiple myeloma
remember the values!!!
calcium: >2.75
creatinine: >177
anaemia: <100
**if it doesn’t meet the above criteria then you have smouldering myeloma**
Epidemiology of multiple myeloma
Risk factors for multiple myeloma
- 2nd most common haemato;ogical malignancy
- mostly affects older people- median age is 67 years old
- men>women
- black>caucasians and asians
___
RF: obesity
What % of plasma cells is there in symptomatic multiple myeloma?
>10%
What are the clinical effects of myeloma due to?
- BM microenvironment interaction
- Circulating paraprotein
What is the most notable interaction of myeloma cells with the bone marrow micro-environment?
Produce RANK ligand which stimulates osteoclasts to cause bone resorption
What is the incidence of IgM myeloma?
Very rare (<1% of myelomas)
What does CRAB stand for in myeloma diagnosis?
Calcium (hypercalcaemia, >2.75)
- this is because of stimulation of osteoclasts which release calcium from the bone
Renal (creatinine >177/ eGFR <40)
Anaemia
- this is because of infiltration of plasma cells into the bone marrow
Bone disease (see lytic lesions)
- bone pain caused by infiltration of bone by plasma cells
What is the most common and 2nd most common cytogenetic abnormality in myeloma?
- Hyperdiploid karyotype: with extra copies of chromosome
- IgH gene rearrangement: chromosomal translocation of chromosome 14q32- locus for IgH gene
note these also occur in MGUS and smouldering myeloma. further secondary events causes progression into multiple myeloma e.g. (but not limited to):
- Commonly mutations of NRAS and KRAS
- Other translocations e.g. of Myc
What are the 3 2014 Myeloma Defining Events
BM plasma cells >60%
involved:uninvolved FLC ratio >100
>1 focal lesion on MRI
Which part of the skeleton is affected by myeloma?
Proximal skeleton (spine, ribs, pelvis, femur, skull, knees)
Where are myeloma patients most likely to feel pain?
Back, chest wall, pelvis
What % of myeloma patients present with bone disease?
80%
What scan is necessary to detect bone lesions in myeloma?
Whole body CT is first line (X ray is obsolete for this use)
PET scan can also be used - (often used in combination with CT/MRI)
Gold-standard = whole body diffusion-weighted MRI as this shows active vs treated disease
What are the 3 most likely emergency presentations of myeloma?
Cord compression- due to soft tissue mass or pathological fracture of vertebrae
Hypercalcaemia
renal failure
What tests should be done to diagnose myeloma?
First:
Serum protein electrophoreis- very sensitive screening monitoring: 24 hour bence jones protein
Serum free light chains
Next:
Bone marrow aspirate- demonstrate infiltration by malignant plasma cells
biopsy for immunohistochemistry: CD138
FISH (for prognostic)
Flow cytometry immunophenotyping: important after treatment to detect small amounts of residual disease if present
What is the best way to treat cord compression in myeloma?
Dexamethosone
Radiotherapy