He feared that if he revealed the truth too soon, the masses would be jolted into a financial panic

On May 5, 1893, during a sensitive period when America was slipping into a depression, President Grover Cleveland secretly discovered a cancerous lump on the roof of his mouth that required urgent surgery. Fearing the news would trigger public panic, he disappeared for four days in July under the guise of a fishing trip and underwent the operation in complete secrecy, a deception that remained hidden for decades, according to a report published in The Surgery Journal.

Reporter Matthew Algeo, who has written about Cleveland’s secret in his book "The President Is a Sick Man," described the circumstance to NPR in his own words. "Shortly after he took office for the second time in 1893, he noticed a little bump on the roof of his mouth," Algeo said. "Around June... he had noticed it had grown quite large. And the doctor diagnosed it as cancer, [saying], 'It's a bad-looking tenant, and I would have it evicted immediately.'"
There were three main reasons why Cleveland wanted to keep the surgery a secret. First, to avoid panic about his health. At the time, his health was already a concern for the public. He was overweight, had gout, loved whiskey and beers, and smoked cigars, per Columbia Surgery. Second, the financial status of the country wasn’t too good during this period. Under the Silver Purchase Act, the US government had to purchase 4.5 ounces of silver every month, which significantly depleted the nation’s gold reserves, also boosting inflation. Cleveland feared that a problem with his health could provoke financial panic among the masses.

The third reason, as Algeo described, was the stigma attached to cancer. "It would be a big deal today," he explained. "It was an even bigger deal then because at the time there was a stigma attached to cancer. Newspapers would call it 'the dread disease.'" And so, he decided to get the tumor removed secretly. As planned, he took a friend’s yacht, the Oneida, announcing it as a four-day fishing trip from New York to his summer house in Cape Cod. On July 1, Dr. Joseph Bryant, along with a team of six surgeons, boarded the yacht and prepared for his surgery.
The surgery took about 90 minutes, during which the surgeons used nitrous oxide, cocaine, and ether to anesthetize him, and then removed the cancerous tumor together with the nearby portions of the hard palate, a segment of the left maxilla, and five teeth. According to an account by the BJS Academy, to ensure that the surgery remained under wraps, the surgeons left no noticeable scarring, even leaving Cleveland's trademark mustache untouched.

Grover Cleveland’s case was one of several moments in U.S. history where presidents hid serious medical conditions because of various factors, according to The New Yorker. For instance, Woodrow Wilson suffered a severe stroke in 1919, but the White House hid how incapacitated he really was. Franklin D. Roosevelt also kept the seriousness of his heart disease and declining health largely hidden during World War II. Moreover, John F. Kennedy privately struggled with chronic illnesses, severe back pain, and Addison’s disease, though the public mostly saw him as young and healthy.
On July 5, the Oneida arrived at Buzzards Bay, but reporters grew suspicious after the trip took far longer than expected. Two months later, reporter E.J. Edwards revealed Cleveland’s secret surgery, though the president denied it and discredited him. Nearly 20 years later, Dr. William Williams Keen finally confirmed the story, by which time the country was stable and the secret no longer mattered.
For 20 years, a millionaire hid his family fortune from his son to teach one powerful lesson