Commonest type of necrosis is
Ans. c (Coagulative). (Ref. Robbins, Pathologic Basis of Disease, 8th/pg.7-13)Caseation necrosis - Tubercular lymph nodesCoagulative necrosis - Myocardial infarction, sarcoidosisLiquefactive necrosis - Brain infarcts and infections (abscess).TYPE OF NECROSISCOMMMENTSCoagulative necrosis- is a form of tissue necrosis in which the component cells are dead but the basic tissue architecture is preserved.- The affected tissues take on a firm texture.- Presumably the injury denatures not only structural proteins but also enzymes and so blocks the proteolysis of the dead cells; as a result, eosinophilic, anucleate cells may persist for days or weeks.- Coagulative necrosis is characteristic of infarcts (areas of ischemic necrosis) in all solid organs except the brain.Liquefactive necrosis- is seen in focal bacterial or, occasionally, fungal infections, because microbes stimulate the accumulation of inflammatory cells and the enzymes of leukocytes digest ("liquefy") the tissue.- For obscure reasons, hypoxic death of cells within central nervous system often evokes liquefactive necrosis.- If the process was initiated by acute inflammation, the material is frequently creamy yellow and is called pus.Gangrenous necrosis- It is usually applied to a limb, generally the lower leg, that has lost its blood supply and has undergone coagulative necrosis involving multiple tissue layers.- When bacterial infection is superimposed, coagulative necrosis is modified by the liquefactive action of the bacteria and the attracted leukocytes (so-called wet gangrene).Caseous necrosis(term "caseous" = cheese-iike)- is encountered most often in foci of tuberculous infection.- On microscopic examination, the necrotic focus appears as a collection of fragmented or lysed cells with an amorphous granular appearance. Unlike coagulative necrosis, the tissue architecture is completely obliterated and cellular outlines cannot be discerned. Caseous necrosis is often enclosed within a distinctive inflammatory border; this appearance is characteristic of a focus of inflammation known as a granuloma.Fat necrosis- Refers to focal areas of fat destruction, typically resulting from release of activated pancreatic lipases into the substance of the pancreas and the peritonea! cavity e.g. acute pancreatitis (fat saponification).- On histologic examination, the foci of necrosis contain shadowy outlines of necrotic fat cells with basophilic calcium deposits, surrounded by an inflammatory reaction.
Fatty
Caseous
Coagulative
Liquifactive
Cellular Pathology