AN UNSIGHTLY scar is often a matter of concern to a patient who acquires such a disfigurement. For this reason, if for no other, it should be a matter of concern to the surgeon. Perhaps the commonest causes of scar disfigurement are hypertrophy of scar tissue and keloid formation. The two conditions are frequently confused, and it is often difficult to differentiate them. The chief differences are as follows: (1) The hypertrophic scar remains confined to the area of skin incision or injury; the keloid tends to invade the surrounding skin. (2) The hypertrophic scar continues to grow for several weeks or months, then becomes inactive and tends to regress; the keloid, however, continues its growth into bizarre conglomerate forms which do not regress. In fact, that is how it derives its name, keloid being a derivation of the Greek word meaning claw. Though these clinical differences are obviously important,