Inexpensively? I don't believe so.
What you are seeing is typically referred to as a "pressure spot". Usually caused by something being sat on the LCD for a period of time (think: putting a heavy book on top of the closed Thinkpad). The only way I know of getting rid of that problem is getting rid of the entire panel. I suppose you could try to disassemble the panel and figure out what has been damaged and replace just that piece (polarizer, probably), but IMO, you'd be better off simply buying another panel.
Since we seem to be talking about a T22 here, if your existing panel is an XGA (1024 x 768), you could replace it with an SXGA+ (along with the LCD ribbon cable) and get the benefit of the larger 1400 x 1050 resolution. Of course, that type of panel is fairly expensive, which goes against your original question/request

.