What is a keloid?

A keloid also represents excessive collagen deposition at a site of wound healing. Clinically, a keloid can be indistinguishable from a hypertrophic scar, though the excess collagen deposition of a keloid is usually more exaggerated. Microscopically, developed keloids can be differentiated from hypertrophic scars by the presence of large eosinophilic collagen fibers and more abundant mucin. Also, unlike hypertrophic scars, keloids uncommonly undergo involution, and they frequently proliferate well beyond the bounds of the original trauma. Some keloids, particularly on the sternum or upper back, even seem to develop without preceding trauma.