Necrosis is the death of cells and living tissue. There are several types of necrosis that are characterized by the microscopic appearance of dead cells. Coagulative necrosis occurs due to ischemia and results in pale, swollen tissue on gross examination and swollen eosinophilic cells on microscopy. Liquefactive necrosis occurs due to infection and results in soft, cystic lesions containing debris. Caseous necrosis is seen in tuberculosis and resembles dry cheese with granular debris. Fat necrosis affects pancreatic and breast tissue, appearing as yellowish deposits containing calcium salts. Fibrinoid necrosis involves fibrin deposition in tissues damaged by immune processes.

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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