Types of Necrosis

Question 1

Coagulative

Answer 1

• Cell shape and organ structure remains stable (architecture fine) due to coagulation of proteins
• BUT nucleus disappears
• Occurs w/ ischemic infarction of all organs except brain
• Can be pale (no blood) OR red (if blood re-enters the infarction - requires loosely organized tissue to hold the blood)
• Often in wedge-shape

Question 2

Liquefactive

Answer 2

• Liquefied b/c enzymatic breakdown of both cells and proteins
• Seen in brain infarct (b/c microglial cells release proteolytic enzymes)
• Seen in abscesses (b/c neutrophils release proteolytic enzymes)
• Seen in pancreatitis (b/c proteolytic digestive enzymes of pancreas)

Question 3

Gangrenous

Answer 3

• Coagulative necrosis that resembles mumified tissue
• Can be dry or wet (superimposed infection)
• Common in lower limb and GI tract

Question 4

Caseous

Answer 4

-Soft, friable, cottage-cheese like tissue

-Liquefactive necrosis + fungus or Tb to thicken it up to cottage cheese consistency
(combo of liquefactive and coagulative)

-Seen when granulomas form to wall off Tb or fungus

Question 5

Fat

Answer 5

• Necrotic adipose tissue becomes white due to Ca deposition
• Ex) trauma to fat (breast) or peri-pancreatic fat in pancreatitis
• Fatty acids released due to trauma or lipases (pancreatitis) –> FAs + Ca –> saponification (“dystrophic calcification - normal serum Ca levels)

Question 6

Fibrinoid

Answer 6

• Necrotic damage to blood vessel wall
• Proteins (including fibrin) leak into vessel wall –> bright pink staining of wall on histo
• Seen in malignant HTN (too much pressure on vessel wall) and vasculitis and in placenta if pre-eclempsia