Danielle Kang, one of the world's best golfers, revealed she's been playing in the U.S. Women's Open with a tumor on her spine.
The 29-year-old made the shocking revelation on Friday ... saying she received the diagnosis from doctors "a few weeks ago."
Kang -- the #12 player in the world -- said she's undergone extensive testing, and is waiting for doctors to tell her if the tumor is benign or malignant.
"I’ve gone through a lot of procedures so far, and with the process of elimination, we are narrowing it down,” she said Friday.