Abstract
The term "dysplastic" melanocytic naevus has recently been used to describe pigmented naevi with unusual histological and clinical features. There is currently no clear clinical or pathological definition of the term, and this has led to a lack of comparability of material described in reports on these lesions. As a result of careful histological study and a clinicopathological correlation of 100 naevi, we suggest that three distinct groups of histopathological features distinguish so called dysplastic naevi from banal melanocytic naevi. These are architectural atypia, cytological atypia, and a host response. Description of each of these features in routine reports and in published series in place of the loose use of the term "dysplastic" would enable comparisons to be made between series of melanocytic lesions reported from different centres. In the course of this study we observed a considerably increased incidence of naevus type giant cells in the dermal portion of the atypical naevi. These giant cells should not be confused with possibly premalignant cytological atypia.