That's another question....LOL.........I bet that is what you wanted to know in the first place..;-)
As I have said in my previous answer...ALL conditions are treatable.
I guess, that someone you know had symptoms which suggested that a chest X-Ray was indicated and that showed a pleural effusion and a shadow on the lung.
The fluid would have been drained off and the wound extended to evaluate and biopsy the "shadow." So as the two layers of pleura wouldn't "stick" together following drainage and biopsy, talcum powder is commonly used to stop the adhesions.
That is how it is treated, depends upon the result of the biopsy.......cancer or something less sinister.