A 65-year-old man with anterior STEMI died 4 days after onset. Autopsy of the heart would most likely show which histological and gross changes?
- A Waviness of myofibers at the periphery of the infarct, predominantly coagulation necrosis with pyknotic nuclei and loss of cross-striations, and early neutrophilic infiltration predominantly in the first 12-24 hours
- B Granulation tissue with prominent ingrowth of capillaries and macrophage predominance, fibrous scarring at the periphery, and complete macrophage replacement of all necrotic debris
- C Well-defined zone of coagulation necrosis with hypereosinophilic cardiomyocytes, ghost outlines of necrotic cells, abundant neutrophilic infiltration throughout the infarct core, and early macrophage infiltration beginning at the margins ✓
- D Dense fibrous scar with hemosiderin deposits and no remaining inflammatory infiltrate, identical to a 6-week-old infarct
Explanation
At 3-7 days post-MI, the infarct shows: (1) established coagulation necrosis with hypereosinophilic (cooked) cardiomyocytes, pyknotic or absent nuclei, maintained cell outlines (ghost cells); (2) prominent neutrophilic infiltration peaking at days 1-3, now abundant throughout the infarct; (3) early macrophage appearance beginning at the infarct margins (days 3-5). Grossly the infarct is pale yellow-brown. Waviness of fibers is the very earliest change (within minutes-hours). Granulation tissue with capillary ingrowth predominates at 7-14 days. Dense fibrous scar takes 6-8 weeks to complete. This temporal understanding is essential for both diagnosis and medico-legal timing of MI.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
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Written and medically reviewed by the StethoPrep medical team.