Corey Halpin, of Hanover Park near Chicago, was one of them. At age 10, he noticed a dark bump on his upper left arm, thinking during a Boy Scout camping trip that it might even be a tick.
"I pushed it but it didn't move, but it bled," Corey, now 13, recalled.
It wasn't until a few months later, during a spring 2002 visit to his pediatrician, that Corey casually asked his dad if he should mention the odd mole. That led to a referral to a specialist and alarming test results that caught even his doctors by surprise.
Melanoma was until recently almost unheard of in children, and it was a diagnosis that his family wasn't prepared for.
"My husband and I were scared to death" and so was Corey, said his mother, Marge Halpin.
Pediatric melanoma is still uncommon in children, affecting only 7 per million, or about 500, according to 2002 statistics from the National Cancer Institute. But that number has risen from 3 per million in 1982.
Dr. Charles Balch of the American Society of Clinical Oncology, who has specialized in melanoma for 30 years, saw his first pediatric case five years ago. Since then, Johns Hopkins Hospital, where he works, has treated about 20 youngsters, the youngest just 8.