A schoolgirl is suffering from a mystery disease that has caused her to become painfully thin and dozens of tumours to appear on her arm.

Ryza May Cantua, 12, was born a healthy baby in Guimaras province, the Philippines, but she started to lose weight when she was eight-years-old.

Her grandfather, Gudy, took care of her after her parents abandoned her and bought her vitamins and food supplements, thinking the girl only had a dietary problem.

However, Ryza became weak and began to complain of painful inflammations on her right arm.

A year after her inexplicable weight loss, her shocked grandfather Gudy found small peanut-sized masses growing on her arm.

They visited several hospitals but a diagnosis on her condition was never made. Her family did not have enough money to continue making return appointments.

Four years later, the tumours have grown rapidly and have eaten up about four inches of the girl’s arm.

Being the lone guardian of the girl since her parents left, the old man said he could not afford to send her to regular check-ups to the doctor.

The girl’s father had left them when she was still a baby while her mother already has a new family to take care of and has abandoned Ryza.

Gudy said: ‘I feel sad for my granddaughter. I am the only one she has. Her mother is busy with her new family and she could not afford to send her sick daughter to the hospital as well.’

Aside from the tumour on her arm, all they know so far is that she has a growth in her stomach which may be causing her weight loss.

Gudy is now appealing for donations to help with his granddaughter’s treatment.

He said: ‘I don’t want to see her suffer any longer, but I cannot do anything but wait for help.

‘I am grateful to people who give us donations and food. They are a big help to us.’