A lung biopsy from a patient with pulmonary tuberculosis shows an area of necrosis that is granular, amorphous, eosinophilic, and enclosed within granulomatous inflammation with Langhans giant cells. Which pattern of necrosis does this represent?

• A Coagulative necrosis
• B Fat necrosis
• C Fibrinoid necrosis
• D Caseous necrosis ✓

Explanation

Caseous necrosis is the hallmark of tuberculous infection, combining features of coagulative and liquefactive necrosis: the tissue architecture is completely obliterated and the debris appears granular and cheesy grossly. It occurs within granulomas and reflects a delayed hypersensitivity response to Mycobacterium tuberculosis. Coagulative necrosis preserves tissue outlines and is seen in ischemic infarcts, while fibrinoid necrosis characterizes immune complex vascular injury.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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