Not true. The highest level you'll ever see your character reported is 50.
Many people consider level 50 plus realm rank (i.e., RR) 5+ to be "level 51," due to the fact that you gain access to an additional 0.3 dps at that point (same +0.3 dps you get at each additional level under normal circumstances).
In other words, a level 50, RR1-RR4 character is capped at 16.2 dps, while a level 50, RR5+ characters caps at 16.5 dps. That's commonly referred to as "level 51."
There are ten (I think?) Master Levels (MLs) with the advent of Trials of Atlantis (ToA). Perhaps someone is calling them level 51-60?
Nevertheless, all you'll ever see on your character screen is <your character's name>, Level 50 <insert class name here>.