Samples of the tumor were sent to the army medical museum, but the name of the patient was not revealed. The diagnosis was not a malignant cancer, but sveral doctors stated after Cleveland's death that the tumor was a carcinoma.In the 1980s, analysis of the specimen finally confirmed the tumor to be verrucous carcinoma, a form of cancer.
Because of the financial depression of the country at the time, Cleveland decided to have surgery performed in secrecy to avoid further market panic. The surgery took place on July 1, 1893, to give Cleveland time to make a full recovery in time for the upcoming Congressional session. Under the guise of a vacation cruise, Cleveland and his surgeon, Dr. Joseph Bryant, left for New York. The surgeons operated aboard the yacht Oneida as it sailed off Long Island. The surgery was conducted through the president's mouth, to avoid any scars or other signs of surgery. Cleveland was anaesthetised with nitrous oxide and ether, and the surgeons successfully removed parts of his upper left jaw and hard palate. The size of the tumor and the extent of the operation left Cleveland's mouth disfigured. Another surgery was required for an orthodontist to fit Cleveland with a hard rubber prosthesis that corrected his speech and restored his appearance.
A cover story about the removal of two bad teeth kept the suspicious press placated. Even when a newspaper story appeared giving details of the actual operation, the participating surgeons discounted the severity of what transpired during Cleveland's vacation. It wasn't until 1917 that one of the surgeons present on the Oneida, Dr. William W. Keen, wrote an article detailing the operation.