A 50-year-old man dies 12 hours after the onset of severe chest pain. Autopsy shows an occlusive thrombus in the left anterior descending artery. Histology of the myocardium supplied by this artery shows which of the following patterns?

• A Dense collagenous scar tissue
• B Coagulative necrosis with loss of nuclei and striations
• C Granulation tissue with capillary proliferation
• D Wavy fibers with contraction band necrosis and early neutrophilic infiltration ✓

Explanation

At 12 hours, the earliest histological change is wavy fibers at the border zone (stretched viable myocytes), contraction band necrosis (from reperfusion injury), and early neutrophilic infiltration. Coagulative necrosis with loss of nuclei becomes prominent by 12-24 hours but wavy fibers are the earliest sign. Granulation tissue appears by day 5-7. Scar tissue takes weeks.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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