Vatican City
Pope Leo This is the first medical event of his 17-month pontificate.
Here is what we know:
A lung nodule is a small abnormal area measuring less than 3 centimeters (about 1.2 inches) in diameter. It is sometimes detected on a CT scan done to investigate another problem, such as trauma or lung infection, according to the American Cancer Society. Experts say the nodule could be benign or malignant and prompt assessment is important.
If the nodule is cancerous and removed early, the prognosis is “excellent” and surgery alone may be sufficient treatment, said Dr. Stephen Liu, a lung cancer expert at Lombardi Comprehensive Cancer Center in Georgetown.
Leo, 71, is otherwise considered in good health and physical fitness, two positive factors for his recovery. He said the nodule was discovered during “recent medical tests,” and the Vatican said Monday that no particular health problem prompted the check, calling it “routine.”
The Vatican said Leo would undergo surgery in the first days of this week, with a week’s recovery expected. Oncologists who don’t treat it said patients can often be discharged from the hospital after just a few days to recover further at home.
The exact date of his hospitalization and surgery was not released, but Leo had a full list of audiences and appointments Monday morning and afternoon, suggesting he would not leave the Vatican until Tuesday.
The pope will be treated at Rome’s Gemelli Hospital, formerly known as the Agostino Gemelli Polyclinic, a nonprofit Catholic university hospital that is part of the Catholic University of the Sacred Heart. The establishment has a special apartment designed for pontiffs on the 10th floor which includes a private chapel. Leo’s immediate predecessor, Pope Francis, was treated there before his death in May 2025, during a long illness caused by a respiratory crisis.
Saint John Paul II spent so much time in Gemelli that he called it “Vatican III,” in homage to the Vatican itself and the papal summer residence of Castel Gandolfo.
Upcoming activities and trip in question
Leo has several activities planned this week.
In addition to its regular meetings, it is scheduled to celebrate a public Mass Wednesday to conclude a weeklong conference on family ministry. Vatican officials suggested Sunday that he might miss it.
Leo also has a big trip planned for November 6-17 to Uruguay, Argentina and Peru. It’s unclear whether the surgery and recovery will affect the ambitious itinerary, which includes a dozen flights, two helicopter flights and significant altitude changes in Peru. Leo said earlier in his remarks Sunday that he still planned to make the trip.
The Pope remains in control, even unconscious
The Vatican has no specific rules governing who takes over if a pope becomes totally incapacitated. Even unconscious during the operation, Leo remained pope and retained his authority.
Pope Francis remained in charge throughout his long hospitalizations, as did St. John Paul II before him. Both made appointments and issued laws and statements from the hospital. A team of officials already runs the Vatican’s day-to-day operations.
Medical advances and the lengthening lifespans of popes, however, highlighted this gap in church law and prompted the Vatican to prepare for a pope becoming too ill or incapable of governing.
Two days before revealing his planned surgery, Leo confirmed an important appointment. On Friday, he approved Filipino Cardinal Luis Antonio Tagle as the new dean of the College of Cardinals. Tagle, 69, replaces Cardinal Giovanni Battista Re, 92, whose mandate Francis extended a few weeks before his death.
The dean plays an important role in a papal transition. He presides over the funeral of the previous pope and helps lead closed-door meetings of cardinals before the conclave to discuss the future needs of the Church. Although he was less than 80 years old at the start of the conclave, he also presided over the secret election of a new pope in the Sistine Chapel.
The Vatican released a letter that Leon wrote to Ré on Sunday – the day of his announcement – thanking him for his life of service to the Church. He highlighted in particular the role Re played in the recent papal transition, when he celebrated Francis’ funeral.
“I do not think I am wrong in saying that you, Your Eminence, have been and remain one of the best known and most esteemed servants of the Holy See,” Leo wrote.
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