Metaplasia😊

notion image
notion image
notion image
notion image
notion image
  • 100% reversible phenomenon
  • Mechanism: Reprogramming of stem cells.
  • M/c: Squamous metaplasia.
    • Example: Lungs.
      • Ciliated epithelium → squamous epithelium.
      • Causes: 
        • Chronic smokers
        • Vitamin A derangements

Barrett Esophagus

  • Definition: Metaplasia.
  • Change: Normal squamous epithelium → intestinal columnar epithelium.
  • Histology:
    • Presence of goblet cells.
      • Contain acidic mucin.
      • Stains positive for Alcian blue (appears blue).
  • Significance: 
    • Precancerous condition for adenocarcinoma of the esophagus.

Mesenchymal Metaplasia

  • Example: Myositis ossificans
      • Definition: Muscle (myo) → bone (ossificans).
      • Cause: Usually trauma, Massaging
          • Myositis ossificans → darker periphery Parosteal osteosarcoma → uniform density → cleft or string sign
          Myositis ossificans → darker periphery
          Parosteal osteosarcoma → uniform density → cleft or string sign