Multiple Myeloma



  • Normal cells transform into myeloma cells at the hematopoietic stem cell level
  • Pathologic derangements:
    • Tumor cells within marrow lead to bone destruction and cytopenia
    • Immunodeficiency develops secondary to suppression of normal immune functions
    • Myeloma proteins lead to hyperviscosity and amyloidosis
    • Multifactorial renal failure
  • Plasma cell secretions activate osteoclasts, leading to:
    • Bone lysis, pathologic fractures, and neurologic impairment
    • Hypercalcemia (exacerbated by impaired renal function)
  • Anemia due to marrow infiltration and renal insufficiency
  • Immunocompromised due to:
    • Decrease in the number of normal immunoglobulins
    • Qualitative and quantitative defects in T- and B-cell subsets
    • Granulocytopenia
    • Decreased cell-mediated immunity
  • Hyperviscosity secondary to protein accumulation:
    • Leads to high-output congestive heart failure
  • Myeloma light chains accumulate in the renal epithelial cells and destroy the entire nephron
  • Clinical signs such as anemia, renal insufficiency, or lytic bone lesions
  • Complications:
    • Pathologic fractures
    • Hypercalcemia
    • Renal failure
    • Recurrent infection
    • Anemia
    • Spinal cord compression (10% of all multiple myeloma [MM] patients)


  • Incidence: 4/100,000 population:
    • 1% of all cancers
    • 10% of all hematopoietic malignancies
    • 10,000 deaths/yr
  • Mean age at diagnosis is 66 yr
  • Slightly higher incidence in men and African Americans (reason unknown)

Pediatric Considerations
  • Rarely seen in children
  • <2% in patients <40 yr of age

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