VIENNA, Austria (AP) — The man believed to be the first recipient of a human tongue transplant was recovering Tuesday and showed no signs of rejecting the organ, his doctors said.

The 42-year-old patient, who had a malignant tumor on his tongue and part of his jaw, underwent a 14-hour operation Saturday in which doctors amputated his tongue and attached the new one.

Surgeons who performed the transplant said there was no evidence in the medical literature that such an operation had been carried out on humans before, and that they were convinced the procedure was the first.

“The tongue now looks as if it were his own — it’s as red and colorful and getting good blood circulation,” said Dr. Rolf Ewers, head of the team of nine physicians who performed the operation in Vienna’s General Hospital.

“The tongue is just slightly swollen,” Ewers added. “That’s also a good sign which means that probably no transplant rejection has begun.”

But the doctors added that the patient, whose name was not released, faces risks such as infection. He also could still reject the organ and must take medication for the rest of his life to prevent that.

The team will consider the operation successful if the patient, who could no longer open his mouth because of the tumor, regains his ability to eat and speak. Surgeons worked meticulously to attach the nerves of the tongue to the severed nerve endings.

“It’s very unlikely he’ll regain his sense of taste,” Ewers said. “But (regaining) feeling and primarily, movement, would be an optimal result.”

Traditionally, in cases where patients lose their tongues, surgeons remove a piece of their small intestines and graft that onto the tongue stump, the doctors said. Such patients are never able to speak clearly or swallow again, however, and must be fed through tubes.

The recipient’s “new” tongue was removed from a brain-dead donor by a separate team of doctors in an adjacent operating room and quickly handed over for transplantation, said Dr. Franz Watzinger, one of the leading surgeons.

The donor — chosen because his blood type and tongue size matched that of the patient — was then taken off life support.

Ewers said the team of doctors had been preparing for two years to carry out the tongue transplant, but had either lacked a candidate for the operation or an appropriate donor.

“And now finally, after long training, we were able to carry it out,” Dr. Christian Kermer said.