Pediatric Melanoma Difficult to Diagnose and on the Rise
(NEW YORK) -- Melanoma is increasingly affecting children.
While the dangerous and rare skin cancer makes up only 5 percent of skin cancer diagnosis, it accounts for a majority of skin cancer deaths.
In 2013, the American Cancer Society estimated, 76,690 new melanomas will be diagnosed and 9,480 people are expected to die from the disease.
Children make up a tiny fraction of these cases, but a study recently published in the journal Pediatrics found that cases of pediatric melanoma are increasing. Between 1973 and 2009, the study found, cases of pediatric skin cancer rose, on average, 2 percent each year.
Melanoma is also the second most common form of cancer for adolescents and young adults between 15 and 29 years old, according to a 2007 study from the National Cancer Foundation.
Unfortunately, pediatric melanoma can be very difficult to diagnose because the warning signs are often very different than those for adult melanoma. In addition, experts say, testing biopsies in a pathology lab can be inconclusive and occasionally these cancers are only definitively diagnosed after they've grown or spread.
A major factor in surviving a cancer diagnosis is early detection, but the early signs of pediatric melanoma often masquerade as inconsequential skin problems.
Melanoma in children often looks very different than melanoma in adults, often lacking the telltale irregularly pigmented moles. Even lab tests can be inconclusive.
Dr. Ashfaq Marghoob, director of Memorial Sloan-Kettering's regional skin cancer clinic in Hauppauge, N.Y., and spokesman for the Skin Cancer Foundation, said melanoma presents very differently in children versus adults.
"You're asking these doctors to look for zebras," said Marghoob. "If you usually see horses you're not looking for zebras. Their mind is not in tune with looking for these melanomas. The morphology of melanoma in kids is different from adults."
A 2011 study presented at the Pediatric Dermatology Annual Meeting found that 60 percent of children between the ages of 0 and 10 in the study with melanoma did not meet the common melanoma-detection criteria. The criteria is broken down by the "ABCDE warning signs," which stands for Asymmetry, Border irregularity, Color variation and Diameter over six millimeters, and Evolution of the lesion.
For children between the ages of 10 and 20, approximately 40 percent did not strictly meet the ABCDE criteria.
Instead, many children in the study had tumors that were symmetrical and amelanosis (lacking pigment). The differences were so significant that the study's authors proposed creating alternative ABCD criteria for pediatric patients, where A is for amelanosis, B for bumps or bleeding, C for uniform Color, and D for various Diameters or de novo (or new) Development.
Marghoob cautioned that even when doctors look for the right warning signs, they can still have difficulty making the correct diagnosis. One problem is that in young children melanoma can be nearly difficult to distinguish from a benign spitz nevus, a kind of harmless mole.
"The clinical [and] the subclinical morphology, they overlap," said Marghoob. "There are features more commonly seen in melanoma in spitz nevus [and the other way around. Sometimes] one cannot, with 100 percent assurance, know if it's a spitz [nevus] or melanoma."
Marghoob said the overlap between the two conditions is how a child 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.
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