DAVID WALKER/STUFF

Hayley Ryan and her son Karlos, 2, who has been living with a brain tumour for a year.

The high-risk brain operation Christchurch 2-year-old Karlos Ryan is due to have next week has only been performed four times in New Zealand.

Fortunately Karlos, who has lived with a brain tumour for about a year, has a hugely supportive family around him.

"Our family's been amazing," mother Hayley Ryan, originally from Timaru, said.

DAVID WALKER/STUFF

Karlos Ryan, 2, is scheduled for brain surgery on June 12.

"They're always positive and supportive and they keep us positive."

Ryan's partner, Ashley Wilson, has given up his job to look after his sick son, with wider family support including the setting up of a Givealittle page to help Karlos and his parents through his health battle.

Within the first week of the page being created, more than $5000 from 29 people had been donated in preparation for the craniotomy on June 12, which remove parts of the tumour.

"We're certainly blown away by how quickly [the donations have] gone up," Ryan said.

Karlos began experiencing weakness in his left side about a year ago and was diagnosed with juvenile pilocytic astrocytoma. He was then sent to Auckland for urgent surgery to reduce the size of the tumour attached to the top of his brain stem. The procedure appeared to be a success, with minimal side effects, but chemotherapy failed to shrink it further, and in 10 months it had grown back to its pre-surgery size.

"Karlos is certainly having a lot of times of frustration," Ryan said.

"He gets quite upset and confused at times but for the most part he's being his little ratbag self. Kids are so resilient."

Ryan said the surgery Karlos faced had a high risk, with possible side effects ranging from vision loss to reduced motor functions, such as difficulties swallowing and eating.

His last surgery only resulted in slight paralysis in one side of his face, causing his eye and one corner of his mouth to droop.

"We're hoping for another miracle," Ryan said.

The tumour returned so quickly his doctor decided a more advanced surgery was needed this time – a tube will be inserted into the brain to drain the mass.

Since the tumour began to grow again, Karlos has been moving around with a limp, has limited movement in his left arm, and was on round-the-clock pain relief.

Ryan thought anyone would find the family's situation a difficult one.

"Now we're all trying to focus on the positive outcome we had last time," she said.

"It's just really about trying to stay strong for Karlos."

Ryan was raised in Timaru and her entire family still calls the town home, so Karlos gets to visit often, as he did over Queen's Birthday weekend.

His favourite thing to do in town is play with the animals on his grandmother's farm.

"We quite often get to Caroline Bay too," Ryan said. "He loves it down there."

 - Stuff