Necrosis morphology Flashcards
Morphologic patterns of necrosis
-Coagulative
-Liquefactive
-Caseous
-Gangrenous
-Fat
Coagulative necrosis
-Basic morphology of cells retained but have a ghost like appearance and inflammation around it
-Cell proteins denatured
Causes of coagulative necrosis
-Loss of energy
-Oxygen metabolites
-Toxins
Histologic morphology of coagulative necrosis
Basic cell outline retained
-Nuclei shrunken, fragmented or absent
-Eventually get lysis of necrotic tissue
Liquefactive necrosis
-Tissue death in response to neutrophil enzymes ( always there)
-Tissue replaced with pus
-Suppurative inflammation
Causes of liquefactive necrosis
-Pyogenic bacterial infection
-Hypoxia in nervous system
Liquefactive necrotic morphology
-Focal pus accumulation
-Inspissation of pus can give it a caseous (dry and crumbly) look
Histologic morphology of liquefactive
-Neutrophils
-See outer fibrous capsule in mature lesions
-Liquefaction of tissue
-No distinct outline
Caseous necrosis
Type of coagulative necrosis where the necrotic tissue is surrounded by a chronic inflammatory response
-Usually a component of granuloma formation
-Can get liquefaction if there are neutrophils
Causes of caseous necrosis
-Tuberculosis from mycobacterium
-Bacteria with dense waxy capsules
-Fungi
-Foreign bodies
Morphology of caseous necrosis
-Granular
-Friable (cottage cheese) mass
-FIbrous capsule
Histologic morphology of caseous
-Central core of cell debris
-Surrounding zone of inflammation with lymphocytes, plasma cells, and macrophages
-Outer fibrous capsule in mature lesions
Gangrenous necrosis
Subset of coagulative and liquefaction necrosis that has a distinct morphology and location
Three morphologic types of gangrene
-Dry- brown to black shriveled tissue due to infarction and mummification
-Wet- sot , red brown to black due to neutrophils
-Gas- exudative brown to black tissue containing gas from bacterial
Causes of gangrenous necrosis
-Ischemia with desiccation
-Saprophytic bacteria
