Leo told the crowd at his weekly noon blessing that doctors caught the nodule at a "very early stage" and recommended surgery. "Following their advice, I have therefore decided to undergo an operation to remove it," he said. Gemelli is the primary place popes go for medical care.
Vatican spokesperson Matteo Bruni said in a statement that the operation will happen in the first days of this week. He put recovery at about one week. Leo also posted his message on social media.
The Vatican has not said whether the nodule is cancerous. According to the American Cancer Society, a lung nodule is a small abnormal area of 3 cm or less that shows up on a chest or abdomen CT scan. Most are benign, more often the result of "old infections, scar tissue, or other causes," though tests are needed to confirm that. Leo has no known previous health problems. He thanked the crowd for their "spiritual closeness" and said he entrusts himself to their prayers.
His next major international trip is set for early November to Uruguay, Argentina and Peru, and it is unclear whether the surgery changes those plans.
Even with surgery days away, Leo used part of his Sunday address to renew his call for peace in Ukraine.