Pope Leo XIV will undergo surgery in the coming days to remove a nodule on his lung, the Vatican announced Sunday, marking the first major health event of his 17-month pontificate. The 71-year-old pope revealed during his Sunday noon blessing in St. Peter’s Square that the nodule was detected at an early stage and is “circumscribed,” or small and well-localized. The Vatican stated his expected recovery time would be about one week .

The pope’s announcement came during an unusual display of transparency about his health, as he thanked the crowd for their support and entrusted himself to their prayers. The Vatican did not specify the exact date of the surgery, only that it would occur early this week. Vatican officials suggested Leo might miss the closing Mass on Wednesday of a weeklong conference on family ministry .

Medical experts noted that lung nodules are common and often benign, but surgical removal can provide a definitive diagnosis. Dr. Stephen Liu, a lung cancer specialist at Georgetown’s Lombardi Comprehensive Cancer Center, said that if the nodule is cancerous, the prognosis would be “excellent” since it was detected early and surgery alone might suffice as treatment .

Leo, who has no previously known health issues, remains physically active, playing tennis weekly and swimming at the papal summer retreat in Castel Gandolfo. He has a major trip planned to Uruguay, Argentina and Peru from Nov. 6-17, and has indicated he still intends to proceed .