WASHINGTON — Jill Biden ‘s surgery Wednesday to remove a potentially cancerous lesion above her right eye was “proceeding well and as expected,” according to her office.

The first lady and President Joe Biden remained at Walter Reed National Military Medical Center in Bethesda, Maryland, as of midafternoon. They had arrived by helicopter at about 8 a.m.

The update from Jill Biden’s office came after she had been at the hospital for about six hours. A further update was expected after the surgery.

Her office announced a week ago that doctors had discovered the lesion during a recent routine skin cancer screening. She was to have a “common outpatient procedure known as Mohs surgery to remove and definitively examine the tissue,” said Dr. Kevin O’Connor, the president’s physician, in a Jan. 4 memo that the first lady’s office released last week.

That surgery involves cutting away thin layers of skin and examining each layer for signs of cancer, according to a fact sheet from the Mayo Clinic. Doctors keep removing layers of skin and examining them until there are no signs of cancer. The procedure takes less than four hours for most people, and they can go home afterward.

Doctors recommended removing the lesion from the 71-year-old first lady “in an abundance of caution,” O’Connor wrote in the memo.

The Skin Cancer Foundation said the delicate skin around the eyes is especially vulnerable to damage from the sun’s ultraviolet rays.

The surgery was arranged for the morning after the Bidens returned from Mexico City, where the president held two days of talks with the leaders of Mexico and Canada and the first lady met with women, children and her North American counterparts.

In April 2021, the first lady had a medical procedure that the White House described only as “common.” Details were not provided. The president accompanied her to an outpatient center near the campus of George Washington University, and they returned to the White House after about two hours.

Biden also accompanied the first lady to Walter Reed in July 2021 for outpatient treatment after she punctured her left foot while walking on a beach in Hawaii. She had stopped in Hawaii for official events after participating in opening events for the Tokyo Olympics.