Word of warning - about any t-shirt, not just plus size... it may shrink in washing.
Last trip we bought shirts at AK and when I washed them they all shrunk. I got a 2x for DH, XL for myself, and child's size for DS. I was so upset when I took them out of the dryer. My XL was all of a sudden somewhere between a M & L, and DH's 2X was definitely not that anymore. I don't know if it had to do with the fact these were all white T's, but it sure did make me mad!!!
On the other hand, a few years back DH and I bought shirts - XL & 2X - in a bright color and neither has shrunk a bit!
So just be careful, and maybe always wash in cold & drip dry???