The granulomatous reaction is a distinctive pattern of chronic inflammation characterized by nodular aggregation of inflammatory cells, predominantly activated macrophages, which often are transformed into epithelium-like (epithelioid) cells. Other cellular components that may be present in granulomas are lymphocytes, plasma cells, fibroblasts and multinucleate giant cells of Langhans or foreign body type. Granulomas are found in approximately 2.5–9% of all liver biopsies (see Section XIX).
Foreign body granulomas and
Foreign Body Granulomas
Foreign body granulomas are elicited by relatively inert foreign material, such as talc, starch, silicone or fat. Lipo- and mineral oil granulomas also are among foreign body granulomas (see below).