A baby girl kissed on the head by Pope Francis has amazingly defied the odds and beaten a brain tumour after being given just months to live.

Gianna Masciantonio was just a year old when the pope blessed her as he travelled through the streets of Philadelphia in September 2015.

The 81-year-old pontiff had no idea the youngster had a brain tumour when she was held up to his Pope mobile as it passed by.

Gianna’s family has revealed almost three years on that the tumour has disappeared after she underwent chemotherapy, reports the Mirror.

Now aged three, Gianna had been diagnosed with Histiocytosis, a blood disorder that occurs when there is an over-production of white blood cells called histiocytes.

The disorder formed the tumour in the girl’s head.

She had surgery when she was just four-months-old, and doctors didn’t think she would make it to her first birthday.

Her parents credit her recovery to faith and medics at the Children’s Hospital of Philadelphia (CHOP), CBS News reports.

Gianna’s relieved mum Kristen Masciantonio said: ‘She’s doing great. She’s going to attend preschool this fall. She’s so excited.’

Dad Joey Masciantonio added: ‘Seeing your kid run around and seeing her doing the things she’s doing, with what they told us from the beginning, is amazing.’

Gianna was pictured in newspapers and on websites around the world after Pope Francis kissed her head and blessed her with the sign of the cross during his visit to the US city.

Her case was dubbed ‘The Miracle on Market Street’, the street where the blessing happened.

The Masciantonios have donated $50,000 to the hospital that saved her life.

The money came from their foundation called For the Love of Grace, which borrows their daughter’s middle name.

Dr Amish Shah, a paediatric neuro-oncologist, said Gianna had defied the odds by winning her battle.

The doctor said: ‘She’s blown our expectations out of the water in terms of how she’s doing.

‘She’s resilient and she’s tough and instead of taking all this as something to be fearful of, she’s really taking this in stride.