Paediatric melanoma

Melanoma is on the rise in both adults and children. Paediatric melanoma, usually defined as melanoma happening in patients younger than 21 years², is rare with a reported incidence of 5-6/1.000.000. It represents approximately only 1-4% of all melanomas^3,4 and 1-3% of all paediatric malignancies⁵. Because of its rarity, they are not well characterized. The diagnosis is often difficult to establish due to melanoma may present as a nonspecific, non-pigmented lesion or benign-appearing lesion.

The fundamental difference of paediatric melanoma is that the process of mutation is accelerated by a genetic predisposition of the patient increasing the changes to get DNA damage by UV radiation. This early onset of melanoma in children happens to behave similarly as in adults, which is not a common thing to see in medicine.

Types of Paediatric Melanoma

Paediatric melanomas are often divided into three categories:

• Adult-type melanoma: Adult-type melanoma is rarely diagnosed before puberty. Clinically, in younger patients, it shows several similarities to adult melanoma, including evidence of UV-induced DNA damage and similar mutations.
• Spitzoid Melanoma (SM): Spitzoid Melanomas are often moles that may grow into a mass, round in shape and uniform in colour. Therefore, SM does not typically follow the commonly used ABCDE guide (refer to section 3) to diagnosing melanoma. Spitzoid moles can be amelanocytic, meaning that can be uncoloured and ulcerated. Additionally, SMs often lack common adult melanoma genetic mutations. When first discovered in 1948 by Sophie Spitz, SMs were described as "melanomas of childhood". They are more common in children than in adults.
• Congenital Melanocytic Nevus (CNM): CNM are pigmented moles or birthmarks that are present at birth. Current research suggests approximately 1-2% of giant CNM cases develop into melanoma. 

Ocular melanoma and mucosal melanoma are rare forms of the disease and although uncommon, can also occur in children. 

²Stefanaki, C., Chardalias, L., Soura, E., Katsarou, A. & Stratigos, A. Paediatric melanoma. (2017). doi:10.1111/jdv.14299

³Strouse, J. J., Fears, T. R., Tucker, M. A. & Wayne, A. S. Pediatric melanoma: risk factor and survival analysis of the surveillance, epidemiology and end results database. J. Clin. Oncol. 23, 4735–41 (2005).

⁴Austin, M. T., Xing, Y., Hayes-Jordan, A. A., Lally, K. P. & Cormier, J. N. Melanoma incidence rises for children and adolescents: An epidemiologic review of pediatric melanoma in the United States. J. Pediatr. Surg. 48, 2207–2213 (2013).

⁵Kottschade, L. A. et al. Rare Presentations of Primary Melanoma and Special Populations. Am. J. Clin. Oncol. 37, 635–641 (2014).