Microscopic Picture: 1-Maintenance of the tissue architecture (muscle fibers are swollen, homogenous and more eosinophilic. 2-Loss of cellular detail (loss of both longitudinal and cross striations with loss of Cohenheim field. 3-Inflammatory cells among the necrotic fibers (line of defense).
Macroscopic Picture: 1-Grayish-white in color (flesh-fish like). 2-Friable in consistency.
Fibrinoid necrosis It is a local death of collagen fibers in living individual and characterized by injury and fragmentation of collagen fibers especially media of blood vessels.
Pathological Features: 1-Edema tends to separate the collagen bundles. 2-Increase mucopolysaccharide in the ground substance (homogenous bright pink staining material). 3-The collagen fibers are fragmented and transformed into stringy and more eosinophilic mass-like fibrin (fibrinoid necrosis). 4-Chronic inflammatory cells infiltration and fibrosis are seen at these areas.