On June 5 last year, Leicestershire parents Rachel and Ashley rushed their two-year-old son Charlie to the doctor, after noticing a lump on his head.
Doctors told them little Charlie had probably just bumped his head, and eleven hours later, they were sent home.
When the lump still hadn't disappeared a week later, Rachel visited her GP and was again told her son was healthy.
By June 20, the lump had grown in size and her doctor referred her to the hospital, where a doctor told the family Charlie's growth was "insignificant" and to only come back in a fortnight if it had changed in size.
When Rachel demanded an ultrasound, doctors discovered Charlie had a 12cm by 6cm tumour in his stomach, and a 7cm by 3cm tumour on the right side of his head. An MRI on July 6 confirmed the worst: Charlie had stage four neuroblastoma, a a rare cancer of the nerve cells.
Just eight months after he was finally diagnosed, Charlie's parents confirmed he "gained his Angel wings" and had passed away.
"Our superhero Charlie passed away last night in mommy's arms, no more pain baby boy," his parents shared on Facebook.
"You will be forever 3. You have taken a piece of our hearts away with you."
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After his diagnosis, Rachel Round, 28, told The Sun an earlier diagnosis may have made his cancer easier to treat.
"The diagnosis was given on July 6 and this is when our whole world fell apart," she said.
"If they had done a blood test when we first took him in they would have noticed he had an infection in his blood and done further tests.
"It is crazy that it was misdiagnosed for four weeks. It is an aggressive cancer, it forms really quickly so those weeks are crucial."
Rachel quit her job to be by Charlie's side as he underwent gruelling chemotherapy, radiotherapy, surgery and immunotherapy sessions, with his father Ashley, 32, also giving up work to help care for Charlie's seven-year-old sister Olivia.