Clinicians often have a low index of suspicion for malignant cutaneous lesions in children, which can lead to a delay in diagnosis and treatment. Below is a review of the three most common types of skin cancer, including diagnostic features, management, and important distinctions.

Melanoma is a life-threatening malignant neoplasm of melanocytes, the cells that synthesize and deposit the pigment melanin. The incidence of cutaneous melanoma has been increasing more rapidly than that of any other neoplasm, and studies suggest that the rates are rising in children. Although only 2% of all cases occur in pediatric patients, melanomas account for just 5% to 10% of cutaneous malignant neoplasms in prepubescent children. Pediatricians must be aware of the potential for melanoma in children, in order to look for and recognize the lesions early in their progression, when they still may be curable by surgical resection.

The American Academy of Dermatology has adopted the ABCD criteria for morphologic characteristics of a melanoma: asymmetry, border irregularity, color variegation, and diameter >6 mm. Childhood melanoma may also appear atypically with ulceration or a lack of pigment (amelanotic). Dermatologists advise clinicians and patients to be suspicious of the “ugly duckling”—a lesion that stands out from all the others through differences in color, growth characteristics, or associated signs or symptoms. Risk factors for melanoma include a history of congenital nevi, dysplastic nevi, xeroderma pigmentosum, and immunodeficiency states. It is not clear if light skin, hair, eyes, and history of blistering sunburn confer the same increased risk in children that they do in adults.

Primary care pediatricians have the opportunity to observe the growth of benign nevi in their patients over time. Any melanocytic lesion with a substantial, unexpected change, such as rapid asymmetric growth, crusting, ulceration, and color loss, warrants a dermatologic evaluation and, possibly, removal. A skin biopsy is required for any cutaneous lesion that is suspected
of being a melanoma. For smaller lesions, an excisional biopsy that includes a small (5 mm) margin of normal skin is recommended; incisional biopsies are performed for very large lesions. All pigmented lesions that are removed should be submitted for examination by a dermopathologist, particularly as diagnosis by histology may be more difficult in children than in adults. When a diagnosis of primary melanoma is confirmed histologically, re-excision, with margins of >1 cm, is required.

The prognosis of cutaneous melanoma depends on the Breslow depth of penetration, which is a measure of lesion thickness in millimeters. Deeper lesions have a higher risk of local and systemic recurrence. Survival rates are high for melanomas with a Breslow depth of <0.75 mm but drop precipitously with a lesion with deep invasion or metastatic spread. Staging of the lesion is based on adult recommendations and is performed by a careful palpation of the associated draining lymph nodes and the radiologic examination of the lung and liver. A sentinel lymph node biopsy is being used more often to guide management. As there are few studies of chemotherapy in children, a multidisciplinary approach to melanoma treatment is recommended with oncologists, dermatologists, surgeons, and others who specialize in pigmented lesions.

Basal cell carcinoma (BCC) is the most common skin cancer in adults, and the incidence is increasing. The condition peaks in the seventh decade of life and is rare in children. When found in the pediatric age group, it is usually associated with a genetic defect, exposure to high-dose radiotherapy, or scars from a burn or trauma. Although BCC in younger people does not correspond directly with cumulative sun damage, de novo cases may be more common in areas of intense ultraviolet (UV) radiation exposure, such as the southwestern United States. BCC presents as a pink, pearly, telangiectatic smooth papule that enlarges slowly and may ulcerate. It appears most frequently on the head, neck, and upper extremities, with the majority occurring on the face. There have been a few cases of BCC on the eyelids of children. Management of BCC is usually curative and involves electrodessication and curettage (ED&C), simple excision, or Mohs microsurgery (MMS). The advantages of ED&C are that treatment requires minimal time and equipment and no suturing; however, there is no histologic examination of tissue with this method, the site takes a longer time to heal, and the procedure results in a large hypopigmented patch scar rather than the linear scar that results from excisional methods. ED&C is most commonly used on superficial BCC of the trunk or extremities. MMS is indicated when the tumor is recurrent, >2 cm in diameter, located on problematic anatomic areas, or an aggressive histopathologic type (e.g., morpheaform). The recurrence rate for BCC
treated by MMS is approximately 1%, whereas that for standard excision is 5% to 10%, depending on the margins of the excision. Cryotherapy is reserved as second line for patients who cannot tolerate other procedures, and radiation therapy is no longer recommended. Imiquimod (Aldara) is a biologic response modifier that stimulates local cytokine release and T cells, which shows some promise for treating BCC, but has not yet been studied for this use in children.