This presentation describes tissue necrosis

1. NECROSIS
Dr. R. Geetha M.D.
Professor
Department of Pathology
SMC

3. DEFINITION OF NECROSIS
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
CYTOPLASMIC CHANGES
Increased eosinophilia of cytoplasm
Glassy homogeneous appearance
Cytoplasm is vacuolated,moth eaten
Calcification of dead cells.
Appearance of myelin figures
Generation of calcium soaps

7. NUCLEAR CHANGES
1. KARYOLYSIS
Fading of basophilia of chromatin
Due to DNAase activity.

8. 2. PYKNOSIS
Nuclear shrinkage and
increased basophilia

9. 3.KARYORRHEXIS
Fragmentation of pyknotic nucleus

10. TYPES OF NECROSIS
Coagulative necrosis
Liquefactive necrosis
Caseous necrosis
Fat necrosis
Fibrinoid necrosis

11. COAGULATIVE NECROSIS
Preservation of general tissue
architecture-tombstone appearance
of the cells.
Affected tissue is firm
Denaturation of structural proteins
and enzymatic digestion of cells.
Example – Heart, kidney,spleen.

12. NORMAL COAGULATIVE
HEART NECROSIS

13. COAGULATIVE NECROSIS HEART

14. COAGULATIVE
NORMAL KIDNEY
NECROSIS

15. NORMAL SPLEEN COAGULATION NECROSIS

16. LIQUIFACTIVE NECROSIS
The tissue becomes liquid viscous
mass
Material is creamy yellow in color
Seen in brain, abscess.

17. LIQUEFACTIVE NECROSIS BRAIN

18. LIQUEFACTIVE NECROSIS BRAIN

19. NORMAL BRAIN LIQUEFACTIVE NECROSIS

20. LIQUEFACTIVE NECROSIS BRAIN

21. GANGRENOUS NECROSIS
Wet gangrene
Dry gangrene
Gas gangrene

22. WET GANGRENE
Occurs in moist tissues like mouth, bowel,
lung, cervix
Diabetic foot
Bed sores

23. WET GANGRENE INTESTINE

24. WET GANGRENE

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

26. DRY GANGRENE

27. WET GANGRENE DRY GANGRENE
Bowel Limb
Venous obstruction Arterial obstruction
Moist,swollen,dark Dry, shrunken, black
No clear line of Presence of line of
demarcation demarcation
Bacteria present No bacteria
Prognosis poor Prognosis better

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

29. GAS GANGRENE

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

31. CASEOUS NECROSIS LUNG

32. CASEOUS NECROSIS LUNG

33. CASEOUS NECROSIS LYMPHNODE

34. CASEOUS NECROSIS LYMPH NODE

35. CASEOUS NECROSIS

36. CASEATION NECROSIS LYMPH NODE

37. FAT NECROSIS
Seen in pancreas, breast
In acute pancreatitis ,activated
lipase causes fat necrosis.
Grossly visible chalky white
areas.
Presence of shadowy outlines of
necrotic cells.

38. FAT NECROSIS

39. FAT NECROSIS

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

41. FIBRINOID NECROSIS