Table 7. Characteristics of Paraganglioma (PGL) and Pheochromocytoma (PCC) Associated with Susceptibility Genesa continued...
Skin Cancer (Melanoma, Basal Cell Carcinoma, and Squamous Cell Carcinoma)
Melanoma, although rare, is the most common skin cancer in children, followed by basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs).[60,61,62,63,64,65,66,67,68] In a retrospective study of 22,524 skin pathology reports in patients younger than 20 years, investigators identified 38 melanomas, 33 of which occurred in patients aged 15 to 19 years. Study investigators reported that the number of lesions that needed to be excised in order to identify one melanoma was 479.8, which is 20 times higher than the adult population.
In patients younger than 20 years, there are approximately 425 cases of melanoma diagnosed each year in the United States, representing about 1% of all new cases of melanoma. Melanoma annual incidence in the United States (2002–2006) increases with age, from 1 to 2 per 1 million in children younger than 10 years to 4.1 per 1 million in children aged 10 to 14 years and 16.9 per 1 million in children aged 15 to 19 years. Melanoma accounts for about 8% of all cancers in children aged 15 to 19 years. The incidence of pediatric melanoma (in children younger than 20 years) increased by 1.7% per year between 1975 and 2006. Increased exposure to ambient ultraviolet radiation increases the risk of the disease.
Conditions associated with an increased risk of developing melanoma in children and adolescents include giant melanocytic nevi, xeroderma pigmentosum (a rare recessive disorder characterized by extreme sensitivity to sunlight, keratosis, and various neurologic manifestations), immunodeficiency, immunosuppression, history of retinoblastoma, and Werner syndrome.[72,73] Other phenotypic traits that are associated with an increased risk of melanoma in adults have been documented in children and adolescents with melanoma and include exposure to ultraviolet sunlight, red hair, blue eyes,[74,75,76,77,78] poor tanning ability, freckling, dysplastic nevi, increased number of melanocytic nevi, and family history of melanoma.[79,80,81] Neurocutaneous melanosis is an unusual condition associated with large or multiple congenital nevi of the skin in association with meningeal melanosis or melanoma; approximately 2.5% of patients with large congenital nevi develop this condition, and those with increased numbers of satellite nevi are at greatest risk.[82,83]
Pediatric melanoma shares many similarities with adult melanoma, and the prognosis is stage dependent. Overall 5-year survival of children and adolescents with melanoma is approximately 90%.[78,84,85] Approximately three-fourths of all children and adolescents present with localized disease and have an excellent outcome (>90% 5-year survival). The outcome for patients with nodal disease is intermediate, with about 60% expected to survive long term.[78,85] In one study, the outcome for patients with metastatic disease was favorable, but this result was not duplicated in another study from the National Cancer Database.