All of the following statements about keloids are true except:

Keloids and hypertrophic scars both occur aftet injuries operations. Hypertrophic scars remain confined to the original injury site and usually regress spontaneously. By contrast, keloids extend beyond the original wound and rarely regress. Keloids contain abnormally large amounts of soluble collagen and water. Keloids tend to recur after excision, and any surgical therapy should be undertaken cautiously with the patient aware that the result may not be ideal.