A teenager who fell ill on holiday was diagnosed with a "grapefruit-sized" brain tumour which had been growing for two years.
Sian Hopper began getting severe headaches when she was 15 but put it down to stress over her GCSE exams.
But on a family holiday in Devon in April 2018 she became violently sick and 'didn't know where she was'.
She was taken to hospital where doctors carried out CT scan as a precaution.
Sian, from Overseal in South Derbyshire, was told she actually had a brain tumour, Derbyshire Live reports.
Since then she has been had to undergo gruelling treatment, but has remained positive.
Sian, now aged 17, said: "I was getting really bad headaches but I just thought it was down to stress because of my exams.
"A couple of weeks later I went to the opticians and was given some prescription glasses. I started having double vision but again I just thought it was because of the glasses and didn’t really worry about it.
"But it was while I was on holiday in Devon with my family that I took quite ill. I was being violently sick and I didn’t know where I was. I was completely out of it.
"My mum said her instinct told her something was seriously wrong and they took me to a local hospital.
"Even though it was only a precaution the doctors did a brain scan.
"The next thing I know they sat down and told me I had a condition called Neurofibromatosis and that I had a tumour the size of a grapefruit. It had been growing for two years and was life threatening.
"It was really hard to hear that because I knew it was serious.
"I am the kind of person that doesn’t like to be negative. I just thought what can I do about it? What can be done and I just wanted to get it over and done with."
Sian, who is now 17 and currently studying health and social care at Burton and South Derbyshire College, said that she tried to put on a brave face as she could see on the hospital ward that there were youngsters "a lot worse off."
She said: "It was a blur. From the minute I was diagnosed to within 24 hours later I was having a seven-hour operation to remove the tumour.
"I just did my best to put on a brave face. Of course, it had a massive effect on my life. It came to a bit of a standstill. But I thought it was important to stay positive.
"There were obviously down days because it was hard to deal with but I didn’t want people to worry. If I was struggling to cope I didn’t want to show it.
"One of the hardest parts was being on the paediatric ward. I saw some not very nice things which made me realise how lucky I really am.
"When you see a baby who has had no life and is constantly poorly it is heartbreaking.
"I made friends with a two-year-old who has sadly died now and it is devastating to think someone so young can spend their life in the hospital.
"I know sometimes things don’t go well and there could have been a situation where I might not survive but I knew I had already had 15 years."
Despite her courageous attitude, Sian has experienced complications since her first surgery. Due to an increase in cranial pressure in her head, she was fitted with an internal lumber shunt, which is a plastic tube that drains away the excess fluid around her brain, which was a huge threat to Sian’s eyesight.
Since then the teenager has had to have multiple further operations.
But luckily she is on the mend now and even took her GCSE exams while recovering from surgery.
She even hopes to go to university to study paramedic science.
She said: "When it came to my exams I knew I wanted to give them a go. I said to mum and dad that I have been at school for seven years learning and preparing for them. I wanted to sit all of them but my parents and the school decided I could sit four and I passed all of them.
"The tumour has been removed but they left the membrane behind because if they were to remove it there would be a risk of brain damage.
"There is a chance it could come back but at the moment I am on medication and still having six-monthly checks with a neurologist to keep everything under control."
Sian is determined to make the most of her life and has been helping others in the wake of her diagnosis.
She is working with the Childhood Tumour Trust to raise awareness about the condition as she believes that regular scans may have prevented her situation from becoming so serious.
She has also donated hair to Little Princess Trust, and has raised £2,500 which she has donated back to Ward E40, where she was cared for, buying countless toys and resources for the staff, patients and families.
