The tumor is an oncocytoma, which is a benign tumor of the kidney that is often indistinguishable from kidney cancer on x-rays. Doctors say these tumors do not spread, unlike cancerous tumors.
Williams also has a tumor on his left kidney. Doctors say that because the tumor on his right kidney was an oncocytoma, there is a good chance that the tumor on the left kidney is the same.
Doctors will perform a biopsy of the left kidney tumor next week. If that tumor is also an oncocytoma, a second surgery would not be needed.
"We are pleased with how well Coach Williams is doing. If everything continues to progress as expected, he should be back to his normal activities soon," said Dr. Eric Wallen, professor of urology at UNC, who led the surgical team.
"Number one, I want to express how overwhelmed I have been by the outpouring of support, concern and good wishes by everyone, especially members of the Carolina Basketball family," said Williams. "I've just been blown away by the calls, cards, prayers and well-wishes from people all around the world in and out of the basketball community. My family and I are thankful to all that have expressed your concerns.
"I also want thank the entire medical team and staff at UNC Health Care. The treatment and care were exceptional. My family and I also deeply appreciate the support shown to us. As someone who spends every day stressing the value and importance of a team, I can confidently say that UNC Health Care has an extraordinary team. I can't thank them enough.
"There is still work to be done, but we will continue to deal with that over the next few weeks and get through it with the help of first-rate medical care and the continued support of my family and our extended family and friends through Carolina Basketball."
Williams is entering his 10th season as the head coach of the Tar Heels and 25th as a college head coach.