True about keloid:
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
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 .