User blog comment:Valyriefaery/Possible Kaneki has ROS since He was a little Theory/@comment-27276334-20151126013802/@comment-3173617-20151126212136

Well I think if you remove it, probably it will grown back and get bigger without any treatment.

I would picture he develops  the growth on his back where his shoulder are like an Ukaku user. I think it would be hard to see if there's a lump on the back.