Samsung PN58A550S1FXZA 58" plasma - blue rectangle

[sweeber]

I have a ~13 year old 58" Samsung plasma, model PN58A550S1FXZA, that recently started showing a bluish rectangle in the upper right hand corner of the screen. It's about 3" wide and extends from the top of the screen halfway down. See the picture below.

https://www.dropbox.com/s/rwuuqq8ift...46.01.jpg?dl=0

The blue rectangle appears on all inputs. The TV otherwise seems to work just fine. Is this a panel issue or something fixable?

Thanks!