Haematology 12: Myeloma And Amyloid, Monocloncal Gammopathy

Question 1

What is monoclonal gammopathy of uncertain significance (MGUS) ?

Answer 1

• IgG/IgA < 30G/L
• <10% clonal plasma cells
• No symptoms (CRAB)
• Genetic errors occur in plasma cell due to infection, inflammation or chromosomal instability.
• This causes monoclonal accumulation of the plasma cells
• This is considered harmless but pre-malignant
• If further mutation, can become multiple myeloma

Question 2

Which mutation can trigger transformation of MGUS to multiple myeloma ?

Answer 2

K-RAS

Question 3

What are the clinical features of Multiple myeloma ?

Answer 3

Calcium - elevated
Renal impairment
Anaemia
Bone lesions

Monoclonal paraprotein (gammaglobulins) 
Bence jones protein in urine (immunoglobulin light chains)

Question 4

What are some of the characteristic features of Multiple myeloma on histology ?

Answer 4

Overcrowding of plasma cells in bone marrow

Plasmacytic cells: Nucleus on one side (eccentric nucleus), dense chromatin, low nuclear to cytoplasmic ratio

Plasmablastic cells: prominent nucleoli, reticular chromatin, less cytoplasm than mature cells

Red cell rouleaux

Question 5

List 3 characteristic finding of multiple myeloma on Immunohistochemistry ?

Answer 5

CD138
CD38
light chain restricted Ig

Question 6

What is fanconi syndrome ?

Answer 6

Renal tubule acidosis with light chain Chrystal depositions

Question 7

What are the 4 main types of treatment for multiple myeloma ?

Answer 7

Cytostatic drug - Melphalan
Steroids
Immuno modulators- Thalidomide
Proteasome inhibitors

Question 8

List the 3 features required to diagnose Multiple myeloma ?

Answer 8

• Clonal plasma cells on bone marrow biopsy
• Paraprotein in blood or urine
• Evidence of end-organ damage - CRAB

Question 9

List the 3 features that are required to diagnose Smouldering myeloma ?

Answer 9

• Serum paraprotein > 30 g/L
• Clonal plasma cell > 10 % on bone marrow biopsy
• No evidence of end organ damage (CRAB)

(This is basically asymptomatic MM)

Question 10

List 3 features required to diagnose MGUS ?

Answer 10

• Serum paraprotein < 30g/l
• Clonal plasma cells < 10 % on bone marrow biopsy
• No signs of end organ damage (CRAB)

Question 11

List 3 features of waldenstrom macroglobinaemia ?

Answer 11

• Low grade NHL (lymphoplasmacytoid)
• Monoclonal IgM
• Hyperviscosity symptoms (visual problems, CCF, weakness, confusion)