A 35-year-old immunocompetent man presents with chronic cough, low-grade fever, and night sweats. Sputum examination is positive for acid-fast bacilli. Lung biopsy is performed. Which type of necrosis is characteristically seen in the granulomas of this infection?
- A Caseous necrosis ✓
- B Liquefactive necrosis
- C Fat necrosis
- D Coagulative necrosis
Correct answer: A. Caseous necrosis
Explanation
The presentation is classic for pulmonary tuberculosis. Tuberculous granulomas show caseous necrosis, which appears as amorphous, granular, eosinophilic debris with loss of cellular outlines on microscopy. Coagulative necrosis is seen in ischemic injury (except brain). Liquefactive necrosis occurs in abscesses and brain infarcts. Fat necrosis occurs in acute pancreatitis and breast trauma.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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