True about keloid:
Ref. Sabiston Textbook of Surgery. Pg. 142
 
Keloid  is the type of abnormal scar formation  and it is most commonly confused with hypertrophic scar .

Keloid scars resemble hypertrophic scars superficially in that they are elevated boundary of the original injury or incision .
Males and females equally prone to keloid scars ,but dark skin types ,especially african genetic origin are 15 times more prone .
Keloid has familial tendency and it spreads beyond wound site
Similarity between keloid and hypertrophic scar is both involves abnormal collagen metabolism resulting in a higher than usual proportion of type 3 collagen and both associated with tissue hypoxia and sustained levels of TGF BETA 1 .
Keloid contain thick collagen and have increased levels of epidermal hyaluronic acid, whereas hypertrophic scars have more nodular microscopic structure with fine collagen bundles and increased conc of alpha actin .
Treatment -intralesional steriods injections .
Wide local excision is treatment of choice
It will have more collagen and vascularity
Will not spread beyond wound site
Elevated levels of growth factor is not seen