Reconstructive surgeon Dr. Maria Siemionow replaced nearly all of the woman's face - 80 percent - with that of a dead female donor in an operation a couple weeks ago.
The patient's name and age were not released. The hospital plans a news conference Wednesday and would not give details until then.
The world's first partial face transplant occurred in France three years ago on a woman who had been mauled by her dog. Two others have been announced since then - a Chinese farmer attacked by a bear and a European man disfigured by a genetic condition.
The nature of the injuries or disfigurement that prompted the Cleveland case are not yet known. Such transplants are controversial, because they are aimed at improving a patient's quality of life rather than saving it, and require recipients to take immune-suppressing drugs for the rest of their life.
"It is very important what kind of recipient they selected," and how great the need was, said Dr. Bohdan Pomahac, a surgeon at Harvard-affiliated Brigham and Women's Hospital in Boston, which plans to offer face transplants too.
"There are patients who can benefit tremendously from this," he said. "It's great that it happened. It is a major move forward. Hopefully it will open the door both to the public and to other centers" wanting to offer such transplants, Pomahac said.
Burn and severe trauma patients have long needed better options, but "the ethics are really controversial" for face transplants, said Dr. Jeffrey Guy, director of the Burn Center at Vanderbilt University.
For the doctors in Cleveland, the task now is balancing two medical risks: the need to give strong immune suppression drugs to prevent rejection, and managing the risk of infection increased by taking such medicines.
Rejection is a possibility whenever someone receives an organ or cells from someone else because the body regards this as foreign tissue. Two types of problems can result.
The first is graft-versus-host disease, which happens if the new facial tissue were to attack the body of the recipient (the host). The second is, if the transplant recipient's body were to attack the marrow or the transplanted face, causing inflammation and other problems at the site of the new tissue.
Either of these can be life-threatening. They can come on suddenly, within days or weeks of the operation, a situation called acute rejection. Or chronic, low-level rejection can set in and slowly undermine the recipient's health.