Photo: George Burns/Harpo Studios

In 2010, Michael reprised one his most famous roles—Gordon Gekko—in Wall Street: Money Never Sleeps. After filming this much-anticipated sequel, Michael says he began having health issues.

"I thought [I had] a sore throat," Michael says. "Sometimes when you're acting, you don't project your voice properly ... it felt like maybe that was what it was."

Over time, Michael experienced more painful symptoms. "[The pain] went back into the back of my gum, and it felt kind of sore there. Then it started going up and towards my ear," Michael says.

Michael says he visited a number of ear, nose and throat doctors in New York City, but no one discovered anything abnormal. Then, while traveling through Canada, he went to see another specialist. "I'll never forget," Michael says. "All he did was put a tongue depressor on my tongue. I just looked—I saw the look in his eye. He pulled back, and he looked at me, and I said, 'Well, I guess we're going to need a little biopsy on that.'"