In acute myocardial infarction, neutrophilic infiltration of the infarcted zone is first seen at approximately:

• A 0–4 hours (very early)
• B 5–7 days
• C 2–3 weeks
• D 12–24 hours ✓

Explanation

The first histological changes in MI (wavy fibers, cytoplasmic eosinophilia) appear at 4–12 hours; neutrophilic infiltration begins at 12–24 hours, peaks by day 1–3, and is then replaced by macrophages. By day 5–7, macrophage-dominated granulation tissue begins forming, and fibrosis is established by 2–3 weeks. This timeline is crucial for dating the infarct at autopsy.

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

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