Tuberculosis granulomas are characterized by which type of necrosis?

• A. Liquefactive necrosis
• B. Coagulative necrosis
• C. Caseous necrosis
• D. Fat necrosis

Answer: (C)

Tuberculosis granulomas are driven by a cell-mediated immune response that walls off the infection, producing a distinctive central area of caseous necrosis. This necrosis is soft, cheese-like, and acellular, with cell outlines lost and a granular, eosinophilic debris core. Surrounding this center are activated macrophages (epithelioid cells) and Langhans-type giant cells, all encased by lymphocytes, reflecting the granulomatous inflamed tissue. This pattern—central caseation within a granuloma—is what sets tuberculous lesions apart from other types of necrosis. Liquefactive necrosis involves digestion into liquid material, coagulative necrosis preserves architecture early on, and fat necrosis occurs in adipose tissue—none of which characterizes TB granulomas.