Twelve-year-old Janet Sylva of Gambia wants to be a doctor when she grows up, she says with a broad grin — one that surgeons in New York gave back to her after removing from her mouth one of the largest tumors they’d ever seen.

The 6-pound benign tumor was about the size of a cantaloupe. It prevented Janet from eating, and her breathing had become so difficult that doctors were afraid she might die within a year if nothing was done.

“It made her a prisoner in her own body,” said Dr. David Hoffman, a Staten Island surgeon who became aware of Janet’s plight last year after doctors in the neighboring west African nation of Senegal reached out to international health groups for assistance. She had stopped going to school and wore a scarf around her face to hide the massive tumor.

Hoffman coordinated with the Global Medical Relief Fund and a team of volunteer surgeons and other medical staff at Cohen Children’s Medical Center in New Hyde Park on Long Island to arrange for Janet to have the surgery, which was performed for free in January.

Dr. Armen Kasabian, chief of plastic surgery at North Shore University Hospital, led the team in performing the delicate operation, which not only involved removing the tumor but also rebuilding her jaw by using part of a bone from her leg. Kasabian said the team knew they had to get it right the first time because Janet and her mother, Philomena, would only be in the U.S. for a short time.

“We don’t have the luxury of operating on her 10 times,” he said. “We have to try and get the most that we can out of just one operation.”