Plasma Cell Dyscrasias

Question 1

What is a normal ratio for kappa and lambda light chains?

Answer 1

0.26-1.65

Question 2

What is the normal plasma cell burden in the bone marrow?

Answer 2

< 1%

Question 3

What imaging workup do all patients with potential plasma cell dyscrasia get?

Answer 3

(1) Skeletal Survey
AND
(2) Low dose whole body CT or MRI if (a) smouldering myeloma or (b) solitary plasmacytoma
AND
(3) One of PET-CT, low dose whole body CT or MRI whole body or spine if suspicious for smouldering myeloma.

Question 4

What are the criteria for a diagnosis of MGUS?

Answer 4

(1) M-spike < 30 g/L AND
(2) BM plasma cells < 10% AND
(3) No end organ damage or biomarkers of malignancy

Question 5

What are the diagnostic criteria for smouldering myeloma?

Answer 5

(1) M-spike > 30 g/L AND/OR
(2) UPEP-spike > 500 mg/24 hrs AND/OR
(3) BM plasma cells 10-60% AND
(4) No end organ damage or biomarkers or malignancy or amyloidosis.

Question 6

What is required to diagnose multiple myeloma?

Answer 6

(1) BM plasma cells > or = 10% or an extra medullary plasmacytoma AND AT LEAST ONE OF:
(A) End organ damage (CRAB features)
(B) Biomarkers of malignancy

Question 7

What are the features of end-organism damage that would be considering defining of multiple myeloma?

Answer 7

C - [Ca 2+] > 2.75 or > 0.25 ULN
R - Renal - Cr > 177 or CrCl < 40
A - Anemia - Hb < 100 g/L or < 20 below LLN
B - Bone - At least 1 osteolytic lesion (skeletal survey, CT or PET-CT)

Question 8

What are the biomarkers of malignancy that would define multiple myeloma even WITHOUT CRAB features(3)?

Answer 8

(1) Bone marrow clonal plasma cells of at least 60%
(2) FLC ratio > 100 with involved light chain > 100 mg/L
(3) > 1 focal bone lesions that are at least 5 mm on MRI

Question 9

What are the risk factors for MGUS transformation to multiple myeloma (3)?

Answer 9

(1) M-protein > or = 15 g/L
(2) Non-IgG M-protein
(3) FLC ratio < 0.26 or > 1.65

Question 10

For low risk MGUS, how do you follow/work them up?

Answer 10

SPEP in 6 months, then Q2 years.

Does not require bone marrow biopsy or bone imaging.

Question 11

How do you investigate high risk MGUS?

Answer 11

If at least one risk factor for progression, need a bone marrow biopsy, skeletal survey & CT abdomen if IgM

Question 12

What investigations would you do in smouldering myeloma to rule out MM?

Answer 12

BM biopsy and aspirate, as well as imaging to rule out bony lesions (CT/MRI).

Question 13

What is the definition for AL amyloidosis?

Answer 13

A plasma cell dyscrasia (or lymphoma) with secondary monoclonal light chain deposition in organs.

Question 14

What are the diagnostic criteria for AL amyloidosis?

Answer 14

Requires ALL 4:

(1) Clonal plasma cell disorder (M-protein, abnormal FLC, clonal plasma cells in BM)
(2) Presence of amyloid related systemic syndrome.
(3) Amyloid on bone marrow or tissue biopsy (will have apple green birefringence on Congo red stain)
(4) Prove amyloid is light chain restricted (mass-spectrometry or electron microscopy)

Question 15

What is the definition of Waldenstrom’s Macroglobulinemia?

Answer 15

(1) A lymphoplasmacytic lymphoma (indolent lymphoma with features between B-cells and plasma cells)
AND
(2) Monoclonal IgM in the peripheral blood

Question 16

What are the clinical features of Waldenstrom’s Macroglobulinemia?

Answer 16

(1) Infiltration Sx - Anemia, hepatosplenomegaly, lymphadenopathy.
(2) Autoimmune Sx - Neuropathy, AIHA, Cold agglutinin disease
(3) Monoclonal IgM Sx - Hyperviscosity, mucocutaneous bleeding, type I croglobulinemia

Question 17

How do you treat hyperviscosity syndrome related to IgM?

Answer 17

PLEX

Question 18

What is the treatment for Waldenstrom’s Macroglobulinemia?

Answer 18

Treat with chemo + rituximab when the patietn becomes symptomatic.

+/- bone marrow transplant