Histopathology and MTLE Practice Test

Granulomatous inflammation is a chronic pattern of inflammation driven by macrophages that are persistently activated to contain irritants that cannot be easily cleared. The hallmark is aggregates of activated macrophages, called epithelioid cells, often with multinucleated giant cells, typically encircled by a layer of lymphocytes. This response is steered by Th1-type cytokines, especially IFN-γ, which boosts macrophage microbicidal activity and keeps the granuloma organized. Over time, granulomas can show central necrosis in caseating forms (as in tuberculosis) or remain noncaseating (as in sarcoidosis); fibrosis may develop as the reaction matures. Because of this cellular makeup and its chronic nature, granulomatous inflammation is not an acute, neutrophil-dominated process, nor is it driven primarily by eosinophils or characterized by minimal inflammation. Therefore, describing granulomatous inflammation as a chronic inflammatory response involving macrophages and giant cells accurately reflects its essential features.