Understanding Necrosis: Types and Morphology

Oct 19, 2024

Notes on Necrosis from Visual Pathology Lab Lecture

Introduction to Necrosis

  • Definition: Necrosis is the result of proteolytic digestion of the cell and its contents.
  • Causes:
    • Release of enzymes such as proteases and endonucleases due to cell injury.
    • Continuous cell injury leads to cell death.

Morphology of Necrosis

  • Different categories of necrosis exist based on the type of organ affected.
  • Visual aids, such as images, will be used to illustrate these types.

Types of Necrosis

1. Coagulative Necrosis

  • Characteristics:
    • Occurs in solid organs that are not soft or rubbery.
    • Enzymatic leakage leads to cell injury and necrosis.
  • Mechanism:
    • Leakage of proteolytic enzymes and rupture of cell membranes.
    • Architecture of the cell remains, but internal content is affected.
  • Examples:
    • Spleen: White areas represent coagulative necrosis.
    • Kidney: Yellowish necrotic area shows infection.
  • Microscopic Features:
    • Loss of cellular contact.
    • Eosinophilia (pinkish coloration of cytoplasm).
    • Nuclear changes: fading of nuclei, shrinkage (pyknosis), and dark color.
    • Comparison with normal tubules shows necrotic patches.

2. Ballooning Degeneration in the Liver

  • Characteristics:
    • Cells become enlarged with eosinophilic cytoplasm and faded nuclei.
  • Comparison:
    • Normal hepatocyte vs. ballooned hepatocyte, showing larger size and degeneration.
    • Accumulation of bile pigments.

3. Myocardial Necrosis

  • Characteristics:
    • Typical example of coagulative necrosis.
  • Microscopic Features:
    • Striated fibers in normal myocardium vs. necrotic myocardium.
    • Eosinophilic cytoplasm and fading nuclei.
    • In severe cases, the tissue may appear dirty due to cytoplasmic degradation.
  • Comparison:
    • Tissue architecture becomes difficult to recognize; only tiny pyknotic nuclei may remain.

Conclusion

  • Coagulative necrosis is a significant pathological process in various organs.
  • Further types of necrosis will be discussed in subsequent videos.