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PA20.3 | Welcome to Multiple Myeloma — Lab Findings & Diagnosis

Learning Objectives

  • Trace the differentiation pathway from B-cell to plasma cell and explain its significance in understanding clonal disorders.
  • Define multiple myeloma and describe the pathogenesis including the role of cytokines and osteoclast activation.
  • List the CRAB features and additional clinical manifestations of multiple myeloma.
  • Interpret the key laboratory findings — M-spike on SPEP, Bence-Jones protein, rouleaux, and bone marrow plasma cell percentage — and explain their diagnostic significance.
  • State the diagnostic criteria for multiple myeloma and distinguish it from MGUS and Waldenström macroglobulinaemia.

INSTRUCTIONS

Multiple myeloma is the archetype of plasma cell dyscrasias — a group of disorders defined by clonal expansion of immunoglobulin-secreting plasma cells. For a Year-2 pathology student, this topic bridges haematology, renal pathology, and bone disease under a single unifying mechanism: a malignant clone that floods the body with a useless monoclonal protein while crowding out normal marrow function. The laboratory findings are among the most clinically distinctive in all of pathology, making this a perennial exam and clinical favourite.

References

  • Robbins & Kumar: Basic Pathology, 11th ed., Ch 12 (Haematopoietic and Lymphoid Systems) (textbook)
  • Harsh Mohan: Textbook of Pathology, 8th ed., Ch 13 (Disorders of Leucocytes and Lymphoreticular Tissues) (textbook)

Version 2.0 | NMC CBUC 2024