Types of Necrosis

Question 1

Coagulative Necrosis

Answer 1

Seen in ischemia/infarcet in most tissues (except brain)

Due to ischemia or infarction; proteins denature then enzymatic degredation

Cell outlines preserved but nuclei disappear; increased cytoplasmic binding of eosin dye

Question 2

Liquefactive necrosis

Answer 2

Seen in bacterial abcess, brain infarcts

Due to: neutrophils release lysosomal enzymes that digest the tissue; enzymatic degradation first, then proteins denature

Histology:

early: cellular debris and macrophages

Late: cystic spaces and cavitation(brain) Neutrophils and cell debris seen with bacterial infection

Question 3

Caseous Necrosis

Answer 3

Seen in TB, systematic fungi, nocardia

Macrophages wall off the infecting microorganism -> granular debris

Histology: Feagmented cells and debris surrounded by lymphocytes and macrophages

Question 4

Fat necrosis

Answer 4

Seen in: enzymatic acute pancreatitis (saponification of peripancreatic fat) nonenzymatic traumatic (eg breast tissue injury)

Damaged cells release lipase to break down triglycerides , liberating fatty acids to bind calcium-> saponifiction

Histology: outlines of dead fat cells without peripheral nuclei; saponification of fat (combined with (Ca2+) appears dark blue on Hand E

Question 5

Fibrinoid necrosis

Answer 5

Seen in immune reactions in vessels, preeclampsia, malignant HTN

Immune complexes combine with fibrin -> vessel wall damage (type III hypertensivity rxn)

Vessel walls are thick and pink

Question 6

Gangenous necrosis

Answer 6

Seen in distal extremity and GI tract, after chronic ischemia

Dry: ischemia

wet: superinfection

Histology:

Dry:coagulatice

wet: liquefactive superimposed on coagulative

Question 7

Answer 7

Coagulative necrosis

Question 8

Answer 8

Liquefactive necrosis

Question 9

Answer 9

Caseous Necrosis

Question 10

Answer 10

Fat necrosis

Question 11

Answer 11

Fibrinoid necrosis

vessel walls are thick and pink

Question 12

Answer 12

Gangrenous necrosis