Malignant Melanoma in the 21st Century, Part 1: Epidemiology, Risk Factors, Screening, Prevention, and Diagnosis

Melanoma Epidemiology and Prevention

“…Nevi A major risk factor for melanoma is number and type of nevi. Nevi are benign collections of melanocytes, and the numbers of nevi have been implicated in numerous studies as the most important risk factor for melanoma, with an increased number of nevi associated with an increased risk of disease [15,24,158,230]. A meta-analysis has shown that individuals with more than 100 normal nevi are at an almost seven times greater risk than individuals with few (≤15) nevi [75,76].…”

“…A meta-analysis has shown that individuals with more than 100 normal nevi are at an almost seven times greater risk than individuals with few (≤15) nevi [75,76]. The increase in risk is also thought to be incremental and proportional to the number of nevi present [158,159]. It has been shown that the presence of 11-25 nevi conferred a 1.5-fold increase in risk compared with fewer than 10 nevi, and this risk doubled with each additional 25 nevi [158].…”

“…The increase in risk is also thought to be incremental and proportional to the number of nevi present [158,159]. It has been shown that the presence of 11-25 nevi conferred a 1.5-fold increase in risk compared with fewer than 10 nevi, and this risk doubled with each additional 25 nevi [158]. The size of the actual nevus also increases the risk of melanoma, especially those greater than 2.0 mm in diameter.…”

“…This subset of nevi are typified by cytological abnormality, with one definition requiring a macular component to at least one area of the lesion and at least three of either: an ill-defined border, an uneven contour, the presence of erythema, and variations in color or size greater than 5 mm [75,76,158]. Individuals with only one atypical lesion are already at a 1.6 times greater risk of melanoma, increasing to a tenfold greater risk with the presence of five or more atypical nevi [75,76].…”

“…Atypical mole syndrome (also known as dysplastic nevus syndrome or familial atypical multiple mole and melanoma syndrome) is a rare phenotype characterized by at least two atypical nevi, high numbers (>100) of normal nevi and nevi on unusual body sites, such as the scalp, soles of the feet, buttocks, or breasts [15,158]. Individuals with atypical mole syndrome, especially in conjunction with a family history of melanoma, are at an even greater risk of developing melanoma.…”