Necrosis and its Types

1. NECROSIS
By,
Mohamed Faizal Asan
DEPARTMENT OF GENERAL
PATHOLOGY

2. What is Necrosis of a cell?
 Necrosis is defined as a localised area
of death of a tissue followed by
degradation of tissue by Hydrolytic
enzymes liberated from Dead cells,It
is invariably accompanied by
inflammatory reaction

3. What happens in necrosis?
 1) Cell digestion by Lytic enzymes :
Cells become
homogeneous with eosinophilic
cytoplasm
sometimes it may also
ungergo vacuolation or dystrophic
calcification.

4.  2)Denaturation of proteins :
Nuclear changes happens
PYKNOSIS – The nucleus shrinks
resulting in condensation of neuclear
chromatin.
KARYOLYSIS – Dissolution of the
nucleus.
KARYORRHESIS – The nucleus
frangments into granular clumps.

5. Types of Necrosis
 Coagulative Necrosis
 Liquefactive Necrosis
 Caseous Necrosis
 Fat Necrosis
 Fibrinoid Necrosis

6. 1.Coagulative Necrosis
 Most common type of necrosis
 Occurs due to a focal irreversible
injury by Ischemia
 Common organs
affected:Heart,Kidney,Spleen
 Gross appearance:They appear
pale,swollen,yellowish and softer,On
progression they become shrunken

7. Coagulative necrosis of a kidney
Histological appearance :
•Conversion of normal cells
IntoTombstones.(Main Hallmark)
•Necrosed cells are swollen and become
more eosinophilic

8. 2.Liquefactive Necrosis
 Also called as Colliquative necrosis
 Occurs due toIschemic injury and
bacterial and Fungal infection.
 Common Examples:Infract
brain,Abscess cavity
 Gross Appearance:Initially soft with a
liquefied centre later a cyst wall is
formed.

9. Liquefaction necrosis of a Brain
•Histologic apperance:
•Cystic spaces with necrotic debris
•Macrophages filled with Phagocytsed
material.

10. Caseous Necrosis
 Combination of both Coagulative and
liquefactive necrosis
 Found in centre of foci of Tuberculous
infection.
 Gross Appearance:Resembles dry
cheese and are
soft,Granular,Yellowish colour.

11. Caseous necrosis of a TB lymph
node
 Histologic Appearance:
 Necrosed foci that are
Structureless,eosinophilic with
Granular debris.
 Consists of Langerhans Giant cells.

12. Fat Necrosis
 Special form of cell death occuring at
two anatomically different locations
but morphologically similar lesions.
 Example:Acte pancreatic Necrosis
and Traumatic Necrosis common in
Breasts.
 Gross Appearance:Yellowish white
firm Deposits,Formation of ncalcium
soaps within the Necrosed foci firmer
and chalky white appearance.

13. Fat Necrosis in Acute Pancreatitis
 Histologic Appearance:
 Necrosed cells with a cloudy
appearance.
 Formation of calcium soaps within the
tissue.

14. Fibrinoid Necrosis
 Characterised by Depsition of fibrin
like material which has the staining
properties of Fibrin.
 It maybe due to various Immunologic
tissue injury(Example:Immune
complex vasculitis,Peptic ulcer……)
 Gross Appearance:Local hemorrhage
may be seen around the site of
Necrosis.

15. Fibrinoid Necrosis in Autoimmune
vasculitis
 Histologic Appearance:Bright
eosinophilic Hyaline like deposition
near the affected vessel wall.
 Necrotic focus surrounded by Debris
of Neutrophils.

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