Can Keloids Have Cancer Cells in Them?

Keloid scars have an abundance of collagen and exhibit a loss of cellular control. Although benign, keloid scars, like any other tissue exposed to chronic inflammation, can theoretically transform into dysplasia or frank carcinoma. The risk of this is very low and not routinely observed clinically. If you have a suspicion, it is always wise to go with your hunch and have the keloid examined.

It would be extremely rare to have cancer develop in a keloid and that is generally not a reason to remove them.
That being said, any chronic wound or old injury can develop a cancer. This has been observed in burn scars and pressure sores and even has a name: Marjolin's ulcer.
There may be other ways to treat the pain. Radiation therapy may be useful for recalcitrant keloids. Recent reports of the use of chemotherapy (5-FU) has also show some benefit. Discuss your options with a plastic surgeon

You would not have cancer cells in the keloid. It is either one of the two and highly unlikely cancer. Keloids can be quite painful, and also they can itch quite a bit. It is felt that a keloid, which is coarse and large collagen fragments that lack the order of normal collagen, can trap small nerve endings and render them painful or pruritic (ithing).
If injections have not worked, and you seem to be in quite a bit of distress. I would seek the help of a plastic surgeon who is experienced in keloid removal. It has to be removed down to the fat and with good margins. Then low grade x ray treatment, laser, and/or steroid injections can be given to prevent its recurrence.
Good luck.