Why would it need a touch panel?
Why would I get up to touch it when I can just press a button on the controller or whatever input device?
The only input needed would be a power button and maybe a reset button.
It could be that the liquid in the LCD is leaking out from that side.
Try to apply pressure on that area and see if the black spot changes its size. This won't really help but it would give you a greater idea on what the problem is.
Finally you can replace the screen with a new one.