Correlation of clinical and histopathologic features in clinically atypical melanocytic nevi

To define better the evolving entity of dysplastic melanocytic nevus (DMN), studies correlating clinical with histologic features of DMN are essential. However, based on a literature search, no previous quantitative analysis was found of the relationship between gross morphologic features and histologic features of DMN. The authors correlated individual clinical features with histopathologic features and histologic diagnosis of the clinically most atypical nevus in 153 melanoma patients. This nevus was identified, evaluated clinically, and removed for histologic evaluation from each patient. Gross morphologic features assessed for nevi included: size (in mm), the presence of a macular component, irregular border, ill-defined border, haphazard coloration, distortion of skin cleavage lines on tangential lighting, asymmetry, and number of colors present (12 features in all). Nineteen histologic features were assessed in each nevus by a single dermatopathologist. These included architectural, nuclear, and cytoplasmic parameters ascribed to dysplastic nevi. Each of these histologic features was correlated with the 12 individual clinical features. Seventeen percent of the nevi fulfilled the criteria for the histologic diagnosis of DMN. Among individual nevus parameters, size (in mm), irregular border, ill-defined border, macular component, and pink color were associated significantly with histologic DMN. Nevus size (in mm) and irregular borders correlated with the greatest number of individual histologic parameters. A comparison of clinicopathologic correlations for two different examiners revealed that certain clinical features are probably more important than others for the recognition of dysplastic nevi and that individual examiners have different thresholds for the perception of some gross morphologic features. These observations are relevant to the development of clinical criteria for dysplastic nevi.