Eliana Mann and her mother Tara

When Tara Mann took her daughter Eliana, now 10 years old, to her local GP, the young girl was promptly sent to have further tests, which revealed a massive benign tumour in her stomach, reports the BBC.

Three years ago, Eliana's parents were concerned their daughter was not growing properly (her feet had not grown for a couple of years), not eating well and tired all the time. In addition, her dad, Paul, had noticed her tummy felt quite hard.

In BBC2 documentary series Great Ormond Street, airing on Tuesday, May 15 at 9pm, the parents describe how Eliana's life has since been transformed by an operation to remove a tumour that was "absolutely enormous" and "took up 50% of her abdomen".

Mum, Tara, told the BBC that if the young girl hadn't had the tumour removed it would have continued to grow, and killed her daughter "just by its size".

"We didn't really have much option - it was a life-saving operation," she explained.

Although Eliana's like a "new girl" now, according to her mum, the operation was a real risk - as there was a one in 10 chance of surgeons not being able to remove the tumour.

During the nine hour-operation, several pieces of tumour were removed - including one that weighed in at more than 3kg and was the size of a small football.

Luckily, the operation was a success, but Eliana - who has since put on weight and gained energy - still needs scans every three months to see if the tumour has returned.