Interesting looking carp

So like a week ago i actually cought something pretty interesting. Ive actually seen photos of carps looking like this, but I never really understood whats going on. Is this result of some injury? Or how comes, that the carp is deformed like this? I mean, he clerly doesnt mind, this one was cought on a river in Czech republic, being 86cm and rougly 13-14kg, so he is doing pretty great. I was just wondering is there is sopmeone in here willing to "name it" or at least explain to me what going on.