A granuloma is a clump of cells that forms when the immune system tries to fight off a harmful substance but cannot remove it from the body.
A necrotizing granuloma is an area of inflammation in which tissue has died. Necrotizing means dying or decaying.
Tuberculosis and Wegener granulomatosis are conditions that cause necrotizing granulomas.
Ferri FF. Granulomatosis with polyangitis (Wegener's granulomatosis). In: Ferri FF, ed. Ferri's Clinical Advisor 2016. Philadelphia, PA: Elsevier Mosby; 2015:55-6.