Chapter 083. Cancer of the Skin (Part 4)

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Management The entire cutaneous surface, including the scalp and mucous membranes, should be examined in each patient. Bright room illumination is important, and a 7x to 10x hand lens is helpful for evaluating variation in pigment pattern. A history of relevant risk factors should be elicited. Any suspicious lesions should be biopsied, evaluated by a specialist, or recorded by chart and/or photography for follow-up. Examination of the lymph nodes and palpation of the abdominal viscera are part of the staging examination for suspected melanoma. The patient should be advised to have other family members screened if either melanoma or clinically...

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Chapter 083. Cancer of the Skin (Part 4) Management The entire cutaneous surface, including the scalp and mucous membranes, should be examined in each patient. Bright room illumination is important, and a 7x to 10x hand lens is helpful for evaluating variation in pigment pattern. A history of relevant risk factors should be elicited. Any suspicious lesions should be biopsied, evaluated by a specialist, or recorded by chart and/or photography for follow-up. Examination of the lymph nodes and palpation of the abdominal viscera are part of the staging examination for suspected melanoma. The patient should be advised to have other family members screened if either melanoma or clinically atypical moles (dysplastic nevi) are present. The detection of early melanoma in relatives has been reported.
Melanoma prevention is based on protection from the sun. Routine use of a broad spectrum UV-A/UV-B sunblock with sun protection factor ≥15, use of protective clothing, and avoiding intense midday ultraviolet exposure should be recommended. The patient should be educated in the clinical features of melanoma and advised to report any growth or other change in a pigmented lesion. Patient education brochures are available from the American Cancer Society, the American Academy of Dermatology, the National Cancer Institute, and the Skin Cancer Foundation. Self-examination at 6- to 8-week intervals may enhance the likelihood of detecting change. The importance of routine follow-up visits for melanoma patients and patients with clinically atypical moles (dysplastic nevi) should be emphasized, as these visits may facilitate early detection of new primary tumors. Precursor Lesions Clinically atypical moles, also termed dysplastic nevi, occur in certain families affected by melanoma. In some families, melanomas occur nearly exclusively in the individuals with dysplastic nevi. In other families, the nevi may not be present in all individuals with an increased risk of melanoma. The melanomas may arise in clinically atypical moles or in normal skin (in the latter situation the moles act as markers of increased risk). Individuals with clinically atypical moles and a strong family history of melanoma have been reported to have a >50% lifetime risk for developing melanoma. Table 83-4 lists the features
that are characteristic of clinically atypical moles and that differentiate them from benign acquired nevi. The number of clinically atypical moles may vary from one to several hundred. Clinically atypical moles usually differ from each other in appearance. The borders are often hazy and indistinct, and the pigment pattern is more highly varied than that in benign acquired nevi. Of the 90% of melanoma patients whose disease is regarded as sporadic (i.e., who lack a family history of melanoma), ~40% have clinically atypical moles, as compared with an estimated 5–10% of the population at large. Further studies to determine the background frequency of clinically atypical moles are required, once greater unanimity exists regarding their clinical and histopathologic features. The observation that sporadic melanomas can arise in association with a clinically atypical mole makes this the most important precursor for melanoma. Less frequent precursors include the giant congenital melanocytic nevus. Congenital melanocytic nevi are present at birth or appear in the neonatal period (tardive form). The giant melanocytic nevus, also called the bathing trunk, cape, or garment nevus, is a rare malformation that affects perhaps 1 in 30,000 to 1 in 100,000 individuals. These nevi are usually >20 cm in diameter and may cover more than half the body surface. Giant nevi often occur in association with multiple small congenital nevi. The borders are sharp, and hair may be present. The lesions are usually dark brown and may have darker and lighter areas. Pigment is haphazardly displayed. The surface is smooth to rugose or cerebriform and may vary from one portion of the lesion to another.
Table 83-4 Clinical Features Distinguishing Atypical Moles from Benign Acquired Nevi Clinical Clinically Atypical Benign Acquired Nevi Feature Moles Color Variable mixtures of tan, Uniformly tan or brown brown, black, or red/pink within a single nevus; nevi may look very different from each other Shape Irregular borders; Round; sharp, clear-cut pigment may fade off into borders between the nevus and surrounding skin; macular the surrounding skin; may be portion at the edge of the nevus flat or elevated Size Usually >6 mm in Usually 10 mm; diameter occasionally
Number Often very many (>100), In a typical adult, 10 to but occasionally may be only 40 are scattered over the body; one perhaps 15% of patients have no nevi Location Sun-exposed areas; the Generally on the sun- back is the most common site, exposed surfaces of the skin but dysplastic nevi may also be above the waist; the scalp, seen on the scalp, breasts, and breasts, and buttocks are rarely buttocks involved Source: Modified from RJ Friedman et al: CA—A Cancer J Clinicians 33(3):130, 1985.