A 45-year-old woman develops a hypertrophic scar over her anterior chest wall 4 months after median sternotomy. Histologically, the collagen fibers in hypertrophic scars compared to keloids show which distinctive pattern?
- A Thick, haphazardly arranged hyalinized collagen bundles within the scar boundary
- B Nodular fascicles of collagen extending beyond wound boundaries
- C Fine, wavy collagen fibers oriented parallel to the epidermis, remaining within wound boundaries ✓
- D Absent collagen with predominantly fibroblast proliferation
Explanation
Hypertrophic scars contain fine, wavy collagen fibers oriented parallel (horizontal) to the epidermis, organized in nodular fascicles but contained within the wound boundary, with higher myofibroblast content. They remain within the original wound margin and may spontaneously regress over 12–18 months. Keloids, by contrast, contain thick, haphazardly arranged hyalinized collagen bundles that extend beyond wound boundaries (claws of growth pattern) and do not regress. This histological distinction correlates with the clinical behavior — keloids recur after excision, while hypertrophic scars have better outcomes with intralesional steroids, pressure therapy, and silicone dressings.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
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