Types of Necrosis Flashcards
Coagulative Necrosis
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
Liquefactive necrosis
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
Caseous Necrosis
Seen in TB, systematic fungi, nocardia
Macrophages wall off the infecting microorganism -> granular debris
Histology: Feagmented cells and debris surrounded by lymphocytes and macrophages
Fat necrosis
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
Fibrinoid necrosis
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
Gangenous necrosis
Seen in distal extremity and GI tract, after chronic ischemia
Dry: ischemia
wet: superinfection
Histology:
Dry:coagulatice
wet: liquefactive superimposed on coagulative
Coagulative necrosis
Liquefactive necrosis
Caseous Necrosis
Fat necrosis
Fibrinoid necrosis
vessel walls are thick and pink
Gangrenous necrosis