Granulomatous Inflammation:

• It is a type of chronic inflammation characterized by accumulation of activated macrophages that assume epithelial cell-like (epithelioid) appearance.
• Under influence of interferon-gamma, activated macrophages gets converted into epithelial cells.
• Epithelioid cells surrounded by rim of lymphocytes is called granuloma.
• Tuberculosis, Johne’s disease, actinomycosis, Actinobacillosis, Schistosomiasis, leprosy and deep fungal infections are classical examples of granulomatous inflammation.
• In case of tuberculosis, combination of hypoxia and free radical injury leads to central zone of necrosis, which have cheesy appearance, so called caseous necrosis. Granuloma forms around caseous necrosis, which is called tubercle, in case of tuberculosis.