Histologic atypia in clinically benign nevi. A prospective study.

Histologic features of dysplastic nevi include varying degrees of pattern atypia, cytologic atypia, and host response. The purpose of this prospective study was to determine the prevalence of these histologic features in benign acquired nevi. Fifty-eight junctional and compound nevi from 26 volunteer subjects were excised and examined. All nevi met each of the following criteria: 5 mm or less in diameter, symmetric, round or slightly oval, uniform pigmentation, distinct and regular margins, and no erythema. One or more of the histologic features associated with dysplastic nevi were present in 87.8% of the lesions; two or more were present in 69%; and all three histologic features were found in 29.3%. These results indicate that histologic features of dysplastic nevi occur in benign common acquired nevi.