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 granulomatosis with polyangiitis are conditions that cause necrotizing granulomas.
Hsi ED, Schnitzer B. Reactive lymphadenopathies. In: Jaffe ES, Arber DA, Campo E, Harris NL, Quintanilla-Martinez L, eds. Hematopathology. 2nd ed. Philadelphia, PA: Elsevier; 2017:chap 9.