dermatologic disorders
Melanoma
Risk Factors for Melanoma
Risk factors for melanoma include Sun exposure, particularly repeated blistering sunburns Repeated tanning with ultraviolet A (UVA) or psoralen plus UVA (PUVA) treatments Nonmelanoma skin cancer Family and personal history of melanoma Light skin, freckling Atypical moles, particularly > 5 Increased numbers of melanocytic nevi Immunosuppression Lentigo maligna Congenital melanocytic nevus > 20 cm (giant congenital nevi) Atypical mole syndrome (dysplastic nevus syndrome) Familial atypical mole–melanoma syndrome Germline mutations in oncogenes, includingBRCA2 Advanced age Patients with a personal history of melanoma have an increased risk of additional melanomas. People who have one or more first-degree relatives with a history of melanoma have an increased risk (up to 6 or 8 times) over those without a family history. Atypical mole syndrome is the presence of large numbers of moles (eg,> 50), at least one of which is atypical and at least one of which is > 8 mm in diameter. Familial atypical mole–melanoma syndrome is the presence of multiple atypical moles and melanoma in 2 or more first-degree relatives; such people are at markedly increased risk (25 times) of melanoma. Melanoma is less common among people with dark skin; when it occurs in people with dark skin, the nail beds, palms, and soles are more often affected. Approximately 30% of melanomas develop from pigmented Diagnosis (about half each from typical and atypical moles); almost all the rest arise from melanocytes in normal skin. Although melanomas occur during pregnancy, pregnancy does not increase the likelihood that a mole will become a melanoma; moles frequently change in size and darken uniformly during pregnancy. The very rare melanomas of childhood almost always arise in the leptomeninges or from giant congenital nevi. In all people, lesions that have certain characteristics of concern, such as size, irregular borders, recent enlargement, darkening, ulceration, or bleeding, should be evaluated (see Diagnosis ). 