Boy, 5, diagnosed with hard-to-spot cancer after falling over and breaking his ...

Last December, five-year-old Derrick 'DJ' Schott tripped and broke his arm as he rushed to get ready to get on the school bus home.

His aunt and uncle Sandra and Charles Tillett, his legal guardians, rushed him to the local ER in Hillview, Kentucky, to get checked out.

Doctors discovered that the kindergartner had broken his humerus, the bone that connects the elbow joint and the shoulder.

The medical team noticed something else on the X-rays: a large mass where DJ's bone was broken.

He was transferred and admitted to Norton Children's Hospital in Louisville for tests and, four days later, the family learned that DJ had osteosarcoma, a type of bone cancer.

Derrick 'DJ' Schott, five (left and right), from Hillview, Kentucky, fell and broke his arm in December 2018 while getting ready to go home from school. Pictured: DJ in the hospital

His aunt and uncle rushed him to the ER to get checked out. Pictured: DJ in the hospital

Derrick 'DJ' Schott, five (left and right), from Hillview, Kentucky, fell and broke his arm in December 2018 while getting ready to go home from school. His aunt and uncle rushed him to the ER to get checked out

Doctors found a large mass where DJ's arm was broken and transferred him to Norton Children's Hospital in Louisville. Pictured: DJ going fishing

Doctors found a large mass where DJ's arm was broken and transferred him to Norton Children's Hospital in Louisville. Pictured: DJ going fishing

According to a GoFundMe page, Charles and Sandra began fostering DJ when he was just three days old.

His mother had used methamphetamine while pregnant and her son had been born with neonatal abstinence syndrome.

This is when a baby withdraws from drugs he or she was exposed to in the womb before birth.

DJ went through withdrawal for about three months. Five months later, the Tilletts formally adopted him. 

Sandra told PEOPLE that DJ has had no other medical issues and that the cancer diagnosis was devastating.

'There were so many things going through our head,' she said. 

'Our first reaction was tears. What do we do from here? What's he gonna go through? Is he gonna be able to keep his arm? It was tears and sorrow.'    

Osteosarcoma is the most common type of bone cancer. It occurs when the cells that grow new bone form a cancerous tumor.

Most tumors usually develop around the knee, either in the lower part of the thighbone or the upper part of the shinbone.

If the cancer has not spread, the long-term survival rate is between 70 and 75 percent.

If osteosarcoma has already spread, such as to the lungs or other bones at diagnosis, the long-term survival rate is about 30 percent.

Just a few days after being diagnosed, DJ began a 10-week chemotherapy regimen.

After four days of tests, the kindergartner was diagnosed with osteosarcoma, a type of bone cancer. Pictured: DJ playing football

After four days of tests, the kindergartner was diagnosed with osteosarcoma, a type of bone cancer. Pictured: DJ playing football

DJ (pictured) is undergoing 10 weeks of chemotherapy, then surgery to remove the tumor

Surgeons will also replace part of his bone with a prosthetic rod that will grow as he does and then give DJ (pictured) seven more weeks of chemotherapy

NEXT Health service initiative offers patients a chance to see a GP on the same day ... trends now