MCQ – 98433

Diagnostic criteria of multiple myeloma includes which of the following?
1. Increased malignant plasma cells in the bone marrow
2. Serum and/or urinary M protein
3. Skeletal lytic lesions
4. Skeletal blastic lesions
Select the correct answer using the code given below:

A.	1, 2 and 3
B.	1, 3 and 4
C.	1, 2 and 4
D.	2, 3 and 4

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Correct Answer » A Explanation

Multiple Myeloma (MM) is a plasma cell malignancy characterized by:

• Monoclonal plasma cell proliferation in the bone marrow.
• Excessive production of monoclonal immunoglobulins (M protein).
• End-organ damage, including bone lytic lesions, renal failure, anemia, and hypercalcemia (CRAB criteria).

Diagnostic Criteria for Multiple Myeloma (IMWG 2014 Criteria)

The International Myeloma Working Group (IMWG) criteria for diagnosis of multiple myeloma require:

A. Clonal Plasma Cell Proliferation (Major Criterion)

1. Bone marrow clonal plasma cells ≥10% OR biopsy-proven plasmacytoma.

B. At Least One Myeloma-Defining Event (MDE):

2. CRAB Features (End-Organ Damage)
   • C: HyperCalcemia (>11 mg/dL or >2.75 mmol/L).
   • R: Renal insufficiency (Creatinine >2 mg/dL or CrCl
   • A: Anemia (Hb
   • B: Bone lesions (Osteolytic lesions on imaging).
3. Biomarkers of Malignancy (Any One)
   • Bone marrow plasma cells ≥60%.
   • Serum free light chain (FLC) ratio ≥100.
   • More than one focal lesion (>5mm) on MRI.

Reason why Option A is Correct:

1. Increased Malignant Plasma Cells in the Bone Marrow 

• Bone marrow biopsy showing ≥10% clonal plasma cells is required for diagnosis.

2. Serum and/or Urinary M Protein (Monoclonal Protein) 

• Detected by Serum Protein Electrophoresis (SPEP), Urine Protein Electrophoresis (UPEP), and Immunofixation Electrophoresis (IFE).
• M protein (paraprotein) is usually IgG or IgA.
• Bence Jones proteins (free light chains) can be detected in urine.

3. Skeletal Lytic Lesions 

• Osteolytic “punched-out” lesions are seen on X-ray, MRI, or PET-CT.
• Caused by increased osteoclast activity (due to RANKL activation by myeloma cells).
• Most common sites: Skull, spine, ribs, pelvis.

Why Other Options Are Incorrect:

4. Skeletal Blastic Lesions 

• Blastic (sclerotic) lesions are NOT seen in multiple myeloma.
• Blastic bone lesions are seen in:
  • Prostate cancer metastases.
  • Paget’s disease of bone.
  • Lymphoma.
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