necrosis

1. NECROSIS

3. DEFINITION
• Spectrum of morphologic changes
that follows cell death in living
tissues.

4. CAUSES OF NECROSIS
ISCHEMIA
PHYSICAL AGENTS
CHEMICAL AGENTS
IMMUNOLOGICAL INJURY

5. PATHOGENESIS OF NECROSIS
1.Denaturation of intracellular proteins.
2.Enzymatic digestion of the cell.

6. MORPHOLOGY
• Increased eosinophilia of cytoplasm
• Glassy homogeneous appearance
• Cytoplasm is vacuolated
• Calcification of dead cells.
• Appearance of myelin figures

7. NUCLEAR CHANGES
1. KARYOLYSIS
2. PYKNOSIS
3.KARYORRHEXIS

8. TYPES OF NECROSIS
• Coagulative necrosis
• Liquefactive necrosis
• Caseous necrosis
• Fat necrosis
• Fibrinoid necrosis

9. COAGULATIVE NECROSIS
• Preservation of general tissue
architecture
• Affected tissue is firm
• Denaturation of structural
proteins and enzymatic digestion
of cells.
• Example – Heart, kidney,spleen.

10. NORMAL
HEART
COAGULATIVE
NECROSIS

11. LIQUEFACTIVE NECROSIS
• The tissue becomes liquid
viscous mass
• Material is creamy yellow in
color
• Seen in brain, abscess.

12. LIQUEFACTIVE NECROSIS BRAIN

13. LIQUEFACTIVE NECROSIS BRAIN

14. GANGRENOUS NECROSIS
• Wet gangrene
• Dry gangrene
• Gas gangrene

15. WET GANGRENE
• In moist tissues like mouth, bowel, lung,
cervix
• Diabetic foot
Bed sores

16. WET GANGRENE INTESTINE

17. DRY GANGRENE
• Toes and feet due to arteriosclerosis
• Thromboangitis obliterans
• Raynaud disease
Trauma

18. DRY GANGRENE

19. GAS GANGRENE
• Wet gangrene caused by gram
positive anaerobic bacteria
• Seen in muscle and in colon

20. GAS GANGRENE

21. CASEOUS NECROSIS
• Type of coagulative necrosis
• Seen in tuberculous infections
• Tissue is cheesy white in appearance
• The tissue architecture is preserved

22. CASEOUS NECROSIS LUNG

23. CASEOUS NECROSIS LYMPH NODE

24. FAT NECROSIS
• Seen in pancreas, breast
• Grossly visible chalky white
areas.
• Presence of shadowy outlines of
necrotic cells.

25. FAT NECROSIS

26. FAT NECROSIS

27. FIBRINOID NECROSIS
• Deposition of fibrin like material
• Seen in immunologic cell injury,
hypertension ,peptic ulcer.

28. FIBRINOID NECROSIS

29. References
Robbins and Cotran Pathologic
Basis of Disease, 10th Ed

30. THANK YOU