Image copyright Rhian John / Hook News Image caption McKenzie John is due to undergo proton beam therapy next month

An eight-year-old boy who complained of neck pain while his mother washed his hair was diagnosed with a rare cancer.

McKenzie John, from Swansea, is undergoing chemotherapy to treat a nasopharyngeal tumour.

The youngster is being treated in Cardiff, where he is on his second of three rounds of chemotherapy.

His mother Rhian John said: "I'm absolutely heartbroken. I never expected something like this to happen to us."

The 35-year-old added: "It's a hell of a lot for an eight-year-old to cope with. McKenzie is in high spirits, but he has a long road ahead of him."

The NHS health care support worker said her son first complained of a painful neck in November while showering.

In January, a GP dismissed his symptoms as a viral infection.

Ms John said: "He's always been a strong and healthy kid, and he never made a fuss or tried to skip school, so it was unusual for him to complain of this neck pain.

"Whenever he tried to tip his head back to wash his hair, he'd say it really hurt."

Image copyright Rhian John / Hook News Image caption McKenzie's mother said he was "in high spirits"

Various tests came back negative before an MRI scan in March revealed the tumour.

McKenzie spent four days in an induced coma before being transferred to an oncology ward at the Noah's Ark Children's Hospital in Cardiff, where he had emergency "adult doses" of chemotherapy.

Mother-of-four Ms John said her son was "getting on with it".

"McKenzie understands he has cancer, he lost all his hair after his first dose of chemo, but he's getting on with it, taking it in his stride."

He is due to undergo proton beam therapy at The Christie NHS Foundation Trust in Manchester, which opened last year.

About 250 people a year in the UK are diagnosed with the cancer, which affects the part of the throat connecting the mouth and the nose.

A Go Fund Me page set up to help support the family's stay in Manchester has so far raised more than £4,000.