Incidence of atypical nevi in Olmsted County: an epidemiological study

The association of atypical nevi with melanoma and other forms of skin cancer has not been clearly defined.

We studied 631 patients with first lifetime diagnosis of mild, moderate or severely atypical nevus from 2000 through 2005, identified through a population-based approach.

Age at first diagnosis differed significantly between men and women (p<.001). Incidence rates peaked in the second through fourth decades in women and in the third, sixth and seventh decades in men. From 2000 through 2005, the overall age- and sex-adjusted incidence rate of all degrees of atypical nevi was 76.0 per 100,000 person-years. There were no statistically significant associations identified between the degree of atypia and the future development of basal cell carcinoma, squamous cell carcinoma or MM (p = 0.51, p = 0.28 and p = 0.19, respectively).

There is no association between atypical nevi and the subsequent development of non-melanoma skin cancer and MM. Incidence rates of atypical nevi are higher among younger women and older men. The association between degree of atypia and malignant melanoma warrants further study.