A 13-year-old red-haired female with a family history of melanoma in her father and multiple moles presents for a routine physical and is found to have a thin 8 mm pink papule on the right neck that has appeared in the last 6 months and occasionally bleeds when it rubs on a shirt (Figure 147-1). A narrow margin excisional biopsy was performed which revealed invasive melanoma 0.7 mm in depth with 2 mitoses per high power field. She was referred to pediatric surgery where she underwent wide local excision and sentinel lymph node biopsy of the neck, which revealed micrometastasis in one node. After PET scan showed no distant metastasis, she underwent lymph node dissection and was enrolled in a clinical trial through a major referral hospital in the region. Her prognosis is guarded, but similar to adults with the same cancer stage.

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  Although extremely rare, malignant melanoma is the most common skin cancer in children and represents 1 percent of all new cases of melanoma.¹

  
  
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  Between 1973 and 2009, 1230 children in the US were diagnosed with melanoma at a rate of 6 per million overall. Children aged 0 to 9 had the lowest rate at 1.1 per million while children aged 15 to 19 were diagnosed at the highest rate of 18 cases per million.¹

  
  
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  Melanoma incidence is on the rise in adults and children with the incidence increasing in children by 2 percent per year and 4 to 8 percent per year in adults.¹

  
  
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  In the US, the death rate is decreasing among persons younger than 65.²

  
  
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  The lifetime risk of developing melanoma is 1 in 55 for men and 1 in 36 for women.³

Risk factors can be broadly thought of as genetic risks, environmental risks, and phenotypic risks—arising from a combination of genetic and environmental risks. For example, a fair skinned child (genetic risk) who gets a sunburn (environmental) is much more likely to develop freckles (phenotypic) and melanoma. Childhood sun exposure is a significant risk factor for developing melanoma as an adult.⁴

Environmental Risks

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  Exposure to sunlight.

  
  
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  History of sunburn doubles the risk of melanoma and is worse at a young age.

  
  
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  Artificial tanning.

  
  
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  History of immunosuppression.

  
  
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  Higher socioeconomic status (likely associated with more frequent opportunity for sunburns).

Genetic Risks

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  Fair skin, blue or green eyes, red or blonde hair.

  
  
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  In children, female sex is higher risk, in adulthood, male sex is higher risk.

  
  
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  Melanoma in a first-degree relative.

  
  
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  History of xeroderma pigmentosa or familial atypical mole melanoma syndrome.

  
  
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  Personal history of a BRCA2 mutation confers a high risk of uveal melanoma.⁵

Phenotypic Risks

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  Many nevi.

  
  
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  Congenital nevi (Figure 147-2).

  
  
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  Multiple dysplastic nevi.

  
  
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  Increased age.

  
  
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  Personal history of skin cancer.

Clinical Features

Melanoma in children may deviate significantly from the traditional ABCDE criteria used to assess risk of melanoma.⁶ The traditional ABCDE guidelines are listed below followed by newly proposed guidelines to increase the sensitivity of detecting melanoma in children.

Traditional Abcde Guidelines

ABCDE guidelines for diagnosing melanoma (Figure 147-3).⁷

A = Asymmetry. Most early melanomas are asymmetrical—A line through the middle will not create matching halves. Benign nevi are usually round and symmetrical (Figure 147-4).

B = Border. The borders of early melanomas are often uneven and may have scalloped or notched edges. Benign nevi have smoother, more even borders (Figure 147-4).

C = Color variation. Benign nevi are usually a single shade of brown. Melanomas are often in varied shades of brown, tan, or black, but may also exhibit red, white, or blue (Figures 147-4 and 147-5).

D = Diameter greater than or equal to 6 mm. Melanomas tend to grow larger than most nevi. Note that melanomas in children or adults can present less than 6 mm in diameter (Figure 147-5).

E = Evolving could be in size, shape, symptoms (itching, tenderness), surface (especially bleeding), and shades of color.

Modified ABCD criteria in children were developed and proposed by Cordoro, et al. in a recent large cohort study.⁶ The criteria were developed from the data presented in Figure 147-6 that compared conventional ABCDE criteria with other presenting features of melanoma in children.

In children, particularly those younger than 13, new ABCD detection criteria are needed as many childhood melanomas present as pink or skin colored uniform bumps. The modified ABCD detection criteria are listed below:

A = Amelanotic lesions are more common in children than adults (Figures 147-1, 147-6, and 147-7).