Leo told pilgrims in St. Peter’s Square that the growth was "well-contained" and had been detected at an early stage.
"Recently, during some medical examinations, doctors found a localised nodule in my lung," the 71-year-old pontiff said.
"It was detected at a very early stage and is well-contained," he added.
"The doctors believe it is advisable to intervene, so, following their advice, I have decided to undergo surgery to remove it," he also said. "The operation is already scheduled for the next few days."
The Vatican press office said Leo was expected to take about a week to recover from the surgery, the Reuters news agency reported.
(gs)
Source: Reuters