Marghoob said the overlap between the two conditions is how Kadynce can end up with different labs studying the same biopsy and having different results. In certain situations, Marghoob said, the cancer can only be definitively diagnosed after it's grown or spread to other areas of the body.
"You find out the correct diagnosis by hindsight," said Marghoob. "You get something that's a diagnosed as a bug bite, [but] it's cancerous."
'Once You're a Melanoma Patient, You're Always a Melanoma Patient'
Melanoma is a vicious disease that leaves its host at an increased risk for reoccurrence for the rest of their lives, even if there's no sign of disease after treatment. As a result, doctors do not use the term "cured" when they speak about recovering from melanoma. Instead they aim for "no evidence of disease" (NED.)
John Randall is only a few months into his treatment. He will spend a year receiving chemotherapy on and off. However, Howard said, the 6-year-old has dealt with the drugs "like a champ" without suffering from too many side effects.
He has been able to remain active this summer and even joined the swim team. Howard said he has only missed a few practices because he hasn't felt up to it.
Howard said occasionally her worries about John Randall have come from unexpected scenarios, such as the time another child innocently asked John Randall why he had to wear a large hat with flaps on the side.
"I was always been afraid of the time when he doesn't want to wear [the hat]," said Howard. "He [told the other child], 'My cancer is triggered by the sun ... so if I wear a hat and sunscreen, it will help.' The other child said, 'Oh, I like it.'"
Howard said she felt a significant relief that John Randall could already comprehend a disease he will have to deal with for the rest of his life.
"That was a defining moment for me," said Howard. "He understands, and he's good and I can trust him."
For Kadynce, now 8, reaching the NED stage involved at a year of chemotherapy and eight surgeries over the last five years.
As a result of the chemotherapy, Kadynce suffered fever, chills and nausea from the medication. It also affected the nerves in her feet, causing pain.
"[One person] who took it as an adult [told me], 'It was like walking on broken glass,'" said Royer.
At one point, the medication made Kadynce so sick they had to temporarily suspend treatment so she could recover. Royer added that Kadynce's eyesight had been affected by her year of chemotherapy.
The 8-year-old was also left with a scar on her cheek the size of a silver dollar that has made her the subject of taunts and bullying, according to Royer.
Although, currently, Kadynce has "no evidence of disease," Royer takes her regularly to the doctor to monitor for any signs of the cancer's reoccurrence.
"Once you're a melanoma patient, you're always a melanoma patient," said Royer.
Now that Kadynce has spent nearly five years as an NED patient, Royer has focused on helping other parents who have children with melanoma. She has become involved with the Melanoma Research Foundation and, last year, Kadynce testified before Congress about the disease.
All of the time spent among doctors and in the hospital has left Kadynce with a passion for anything medical, according to Royer.
"She does virtual surgery [on a video game]," said Royer. "She asked for a cadaver for Christmas. I'm still trying to figure that one out."