Surgeons have removed a tumour from the mouth of a foetus, in what has been described as a "world first" procedure.After a scan at 17 weeks, mother Tammy Gonzalez said she "could see a bubble" coming out of her baby's mouth.Doctors said it was a very rare tumour called an oral teratoma and there was little chance her daughter would survive.After the pioneering operation, baby Leyna was born five months later.Doctors at the Jackson Memorial Hospital in Florida, said this type of tumour was so rare it had been seen only once in 20 years at the hospital.'Saviours'In the procedure, Mrs Gonzalez was put under a local anaesthetic as a needle was pushed through the protective amniotic sac around the foetus.A laser was then used to cut the tumour from Leyna's lips. The operation lasted just over an hour.Tammy told a press conference in Miami: "When they finally severed the whole thing off and I could see it floating down, it was like this huge weight had been lifted off me and I could finally see her face."She described the surgeons as "saviours".The doctors said: "To our knowledge, this is the first successful treatment of a foetal oral teratoma in utero."Leyna Mykaella Gonzalez was born in October 2010 weighing 8lb 1oz. She is now a healthy 20-month-old child.The only sign of her life-saving surgery is a tiny scar on her mouth.The details have only just emerged after the operation was reported in the American Journal of Obstetrics & Gynecology.