Keloids are scar tissue built up from wounds, surgical cuts, laser treatment areas, healed areas caused by disease such as lesions, ulcers, etc. The scar tissue is generally a white or dark area made of collagen or other body tissue. It can appear differently on skin of different races. Internal keloids can be benign or cause problems and have to be dealt with surgically or by a dermatologist. They can also be spelled cheloids and some call them colloids but that is not technically correct. See link below.