It isn't uncommon for high-end GPU's to run at 50C-55C. And especially under load like in a high--end game.
I would check your fans and make sure they are in fact running and running correctly. Then if you are really worried about temps, you could always reapply thermal paste which can drop temps even more. In my case, I've come across cards with old or badly applied thermal paste, when I reapplied it, it dropped my temps on the card about 15F. I personally use Arctic Silver 5, my favorite thermal paste.
As long as it doesn't hit 80C or higher you are fine on extreme temps. That's the threshold for temps, much more and you are damaging your components.
You can always bump your fan speeds up with a program like MSI Afterburner. Just be aware the faster your fan is, and the harder it runs, the sooner the fan goes out. I've gone through a few fans running them on 100% speed just because I wanted a colder card.
Hope I helped!