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Granulomatous inflammationDefinition: it is a special type of chronic •inflammation in which the predominant celltype is an epitheloid macrophage(which is anactivated macrophage,so called because of it’ssimilarity to epithelial cells,has vesicular nucleiand abundant cytoplasm ,they have secretoryrather than phagocytic activity).Macrophage giant cell:a large cell having •numerous nuclei,2 main types:

Foreign body GC.Langhan’s GC.Granuloma is a localized focus of granulomatousinflammation,it consist of aggregations ofepitheloid cells surrounded by a rim of lymphocytesand a rim of fibroblast and fibrosis,a giant cells maybe formed,when a central necrosis(caseousnecrosis) is found the lesion is called tubercle.

The basis of formation of granuloma is the inabilityof macrophages to kill a foreign invading particle,instead, this invader survives the inflammation,with the action of all mediators secreted bymacrophages, other macrophages are attractedand form the granuloma.•

Types of granuloma:•1.foreign body granuloma: formed as a reactionto foreign body e.g.: suture, talk…….etc.2.Immune granuloma: formed as a result of •immune reaction to certain antigenic particles.microscopical appearance:it is composed of •epitheloid cells which are large cells withvesicular nuclei abundant pink cytoplasm andindisinct cell borders.•

Causes of granulomatousinflammation1.specific infection: •Mycrobacteria( T.B,leprosy,atypicalmycrobacteria).Parasites(larvae,eggs & worms). •Fungi(brucellosis,syphilis,cat-scratchdisease&yersina.••2.Foreign bodies: •Endogenous(keratin,necrotic bone,sodium ureatecrystals).•

3.Chemicals:BerrylosisDrugs4.unknown:crohn’s disease, sarcoidosis,wegener’sgranulomatosis.