A 25-year-old IV drug user develops fever and tricuspid valve vegetations on echo, growing S. aureus. Histology of infective endocarditis vegetations shows:
- A Sterile fibrin-platelet thrombi with no organisms or inflammation
- B Large irregular vegetations with neutrophilic infiltrate, necrosis, and bacteria within the valve tissue ✓
- C Small, flat, warty lesions along the line of valve closure
- D Calcium deposits with laminated concentric fibrous overgrowth
Correct answer: B. Large irregular vegetations with neutrophilic infiltrate, necrosis, and bacteria within the valve tissue
Explanation
Infective endocarditis produces bulky, irregular, destructive vegetations containing fibrin, neutrophils, necrotic tissue, and colonies of organisms embedded in the valve. Sterile fibrin-platelet thrombi characterize nonbacterial thrombotic (marantic) endocarditis. Small warty lesions along the line of valve closure characterize Libman-Sacks endocarditis (SLE). Calcium/fibrous overgrowth is calcific valve degeneration.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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