U.S. Olympic figure skater Maia Shibutani reveals she has a tumor on her kidney

U.S. Olympic figure skater Maia Shibutani revealed Monday on Instagram that doctors have found a tumor on her kidney.

Shibutani broke the news alongside a photo of her in a hospital bed.

"It's been a really tough week," she began. "Back in October, I got sick and had to go to the ER while I was in New York. It ended up being a stomach virus, but they ran some tests that showed an abnormality - it was recommended that I have a follow-up appointment to take a closer look. After an MRI earlier this week in LA, I was told that I had a small mass on one of my kidneys."

Shibutani, 25, said the development has stunned her and she's already begun treatment.

"Receiving this news has been incredibly shocking and difficult to handle. I've been so scared, but I have had the full support of my family, doctors, and nurses," she wrote. "I had surgery yesterday to remove the tumor. The surgery was successful and I was able to keep the rest of my kidney.

"I am in recovery at the hospital and have been in a lot of pain post-surgery, but I am grateful. My doctor said there is a 60/40 chance that the tumor was malignant versus benign (we will know soon), but I am young, healthy, and feel fortunate that this was detected so early."

Related: Alex and Maia Shibutani

Shibutani skates with her older brother, Alex. They are known as the "Shib Sibs" and won a bronze medal at the 2018 Winter Olympics in Pyeongchang. They also helped Team USA win a bronze medal.

Despite all that's happened, Shibutani, a two-time U.S. national champion, remains optimistic.

"While this is deeply personal news, I don't want rumors to spread, or for anyone to worry in case people say they saw me at the hospital. (Next time, just say "hi") I am going to try and stay positive and focus on my recovery," she wrote. "I appreciate all of the support and good vibes sent my way. My fingers are crossed, too.