Olympic gold medalist Kikkan Randall said on social media Wednesday she’s recently been diagnosed with breast cancer.

Randall, along with U.S. teammate Jessie Diggins, made history in Pyeongchang by becoming the first American female cross country skiers to win an Olympic medal — and it was gold. The five-time Olympian wrote on Twitter that the prognosis is good after the cancer was detected early. “My life will change quite a bit in the coming months,” she tweeted.

She is receiving treatment at a hospital in Anchorage, Alaska, and began her first round of chemotherapy Monday.

"It's a scary thing to learn you have cancer and I have wondered every day since how this could have possibly happened to me," Randall wrote in an Instagram post. "But I have promised myself that I will remain positive and active and determined throughout my treatment.

"I am going to bring as much tenacity, strength, and energy toward this challenge as I have throughout my entire career."

A trailblazer in women’s cross country skiing, Randall, 35, came back from maternity leave to make her fifth U.S. Olympic team. She took off the 2015-16 season and gave birth to son Breck in April 2016.

Until this year’s Pyeongchang Olympics, Bill Koch was the only American to reach the Olympic podium in the sport of cross country skiing, winning a silver medal in the 30-kilometer event at the 1976 Innsbruck Games.

After finishing the World Cup season in Sweden, Randall retired from competition. She finished her career wtih three world championship medals, including gold in the team sprint in 2013.

“It’s been a really amazing journey for me through five Olympics, but it really got fun about six years ago when this women’s team formed and the level has been rising and rising and rising,” Randall said after winning gold in South Korea.

“We talked about, if we won a medal at the Olympics it was truly going to be a team medal whether you were on the snow that day or not. It’s been in the works for a long time and it’s amazing to finally make it happen.”