MI Pathology

Question 1

0-30 min after MI

Answer 1

Microscopic Changes: None
Gross Changes: None

Question 2

30min-4hours

Answer 2

Microscopic Changes: Wavy fibers at the infarct border
Gross Changes: None

Question 3

4-12 hours

Answer 3

Microscopic Changes: Early coagulation necrosis, edema, hemorrahge
Gross Changes: Dark mottling

Question 4

12-24 hours

Answer 4

Microscopic Changes: Coagulation necrosis with prominent neutrophilic infiltrates
Gross Changes: Dark Mottling

Question 5

1-3 days

Answer 5

Microscopic Changes: Late coagulation necrosis with loss of nuclei and striations
Gross Changes: Mottling, yellow tan infarct center

Question 6

3-7 days

Answer 6

Microscopic Changes: Beginning of disintegration of dead myofibers and dying neutrophils
Gross Changes: Hyperemic border, yellow tan center, onset of softening

Question 7

7-10 days

Answer 7

Microscopic Changes: Granulation tissue at the infarct border, phagocytosis of dead cells
Gross Changes: Maximal softening, yellow tan granulation tissue

Question 8

10-14 days

Answer 8

Microscopic Changes: Well-established granulation tissue, onset of collagen deposition, neovascularization
Gross Changes: Red-Gray depressed infarct borders

Question 9

2-8 weeks

Answer 9

Microscopic Changes: Increased collagen deposition, decreased cellularity
Gross Changes: Gray white scar

Question 10

> 2 months

Answer 10

Microscopic Changes: dense type 1 collagen scar formation
Gross Changes: Mature scar