A retrospective look at dysplastic nevi. What were they in 1978 and how have they fared since?

We re-examined histologic sections of 305 melanocytic lesions consecutively received for diagnosis in 1978. Of 237 lesions previously diagnosed as banal melanocytic nevi, 28% were reinterpreted to be dysplastic nevi. Clinical follow-up 5 years later of 28 incompletely removed dysplastic nevi revealed neither persistence of pigment nor development of malignant melanoma at their sites of biopsy. We conclude, therefore, that dysplastic melanocytic nevi were common melanocytic neoplasms in 1978. Furthermore, based on our findings, they may be managed safely by observation with periodic clinical follow-up. Of 61 malignant melanomas studied during the same period in 1978, none occurred in association with a dysplastic nevus. The concept that malignant melanomas commonly arise in dysplastic melanocytic nevi therefore should be re-examined.