What histologic finding is typically seen in myocardial tissue around 24 hours after a myocardial infarction?

• A. Coagulative necrosis with beginning neutrophilic infiltration and dark mottling of the affected area.
• B. Granulomatous inflammation with giant cells.
• C. Fibrosis with scar formation.
• D. Coagulative necrosis with beginning neutrophilic infiltration but no discoloration.

Answer: (C)

Around 24 hours after a myocardial infarction, you’d expect coagulative necrosis of the heart muscle with the beginning of neutrophilic infiltration. The tissue is already showing signs of cell death, and neutrophils start to invade the damaged area as part of the inflammatory response. Grossly, the infarct often appears dark and mottled due to edema and hemorrhage. Fibrosis with scar formation is a later event, developing over weeks as healing progresses and fibroblasts lay down collagen to replace the necrotic tissue. Granulomatous inflammation with giant cells isn’t part of the typical early post-infarction pattern, and at this time point you would expect the infarcted area to have the coagulative necrosis with early neutrophils and the characteristic dark mottling, not a lack of discoloration.