Grossly, a transmural myocardial infarction of 4 days' duration would show which characteristic finding?

• A Pale/coagulative necrosis with no gross change (first 12–24 hours)
• B Yellow-tan, soft area with a hyperemic border (maximum neutrophil infiltration) ✓
• C White fibrous scar (fibrosis complete at 4 days)
• D Green discoloration due to bile staining of infarcted myocardium

Explanation

By days 3–7 post-infarction, the infarcted zone grossly appears yellow-tan and soft (due to neutrophilic liquefaction beginning) with a hyperemic red/brown border. This corresponds histologically to the peak of neutrophilic infiltration (day 1–3) followed by macrophage ingress. At 0–12 hours, there is no gross change. White fibrosis replaces the infarct only from 7 weeks onward. Green discoloration is not a feature of MI.

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

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