OKLAHOMA CITY - 18-month old Jonathan Mauldin can't quit giggling.
He's sitting on the floor, looking up at a therapy dog named Mr. Finn, who is visiting patients at the Jimmy Everest Center for Cancer.
His parents are thrilled Jonathan appears so happy and healthy.
"The new treatment is amazing. He's done almost a 180 degree on us and climbs around the house" says John Mauldin, Jonathan's dad.
Jonathan and Rebecca Mauldin, of Edmond, say their baby is doing better now compared to the entirety of short life.
At just two-weeks-old, they noticed a strange rash on his back.
"The dermatologist said, 'You know, there's a disease that you learn about in medical school but never see, so we're just going to rule it out" says Rebecca Mauldin, when she described taking Jonathan to the doctor shortly after his birth.
What at first appeared to be eczema became more severe. Blisters formed on Jonathan's scalp, and he developed painful lesions in his armpits. Jonathan's diagnosis turned out to be a rare disease called Langerhans Cell Histiocytosis.
Dr. Sayani Tewari, from Jimmy Everest Center for Cancer, says a pediatric oncologist may never see LCH in their entire career.
"In LCH, it's like your immune cells are growing unchecked, and it's not exactly cancer, not malignant, but it acts like cancer so it can involve and spread over your body just like cancer does," he said.
Dr. Tewari says in many cases, the rash disappears and the child naturally is cured. In Jonathan's case, PET scans eventually revealed internal lesions on his liver, spleen and bones that made him feel miserable.
Jonathan is getting chemotherapy and is receiving a new targeted therapy in pill form that has stopped his frequent fevers.
He does really well with the treatment. He's real tired at first, but after a few days, he's playing again," his mother said.
"It's really good to see as a physician the way he was sick and the way he is now. It's worth it," Dr. Tewari said.
The Mauldin's says they love the staff at Jimmy Everest, and the way they clearly explain to them each step of Jonathan's medical journey.
The Mauldins says they're grateful a condition so rare has been met with world-class care here at home. Jonathan is playing again in their Edmond living room with his blocks and toys, just exploring like a toddler should and everyone he knows is praying it will continue.
If you'd like to help kids like Jonathan beat cancer, consider making a donation to JECKids.org.
'Kids With Courage' is sponsored by the Jimmy Everest Center.