Related to scar tissue that has thickened, excessively.

Hypertrophic scars sometimes are difficult to distinguish from keloid scars, but unlike keloids, hypertropic scars remain confined to the injury site and often mature and flatten out over time. Hypertrophic scars are more common in people with lighter complexions.  Scars from the healing of deep second degree burns and those formed at the fringe of a skin graft are prone to hypertrophy.

Hypertrophic scars are thick and raised and often darker in color than surrounding skin. Hypertrophic scar formation is not a part of normal wound healing and can develop over time. These kinds of scars are a problem in patients with a genetic predisposition (tendency) to scarring, and in deep wounds that require a long time to heal.

Resources: Bsttw.Inc