Analysis of interobserver reproducibility in grading histological patterns of dysplastic nevi*

BACKGROUND: Dysplastic nevi are among the most important cutaneous melanoma simulators. They are important risk markers for this neoplasia and can be its potential precursors. Some authors found a statistically significant relationship between the degree of dysplasia and the risk for developing melanoma. However, reproducibility of grading criteria ranged from poor to fair in the researched articles. OBJECTIVE: To test the reproducibility of the grading criteria proposed by Sagebiel et al. regarding dysplastic nevi. METHODS: Histological specimens of 75 dysplastic nevi were graded, independently and in a blinded fashion, according to preestablished criteria, by a panel of 10 pathologists with different levels of experience. Diagnostic agreement was calculated using weighted kappa and intraclass correlation coefficients. RESULTS: The average of weighted kappa values was 0.13 for all observers, 0.12 for dermatopathologists, 0.18 for general pathologists and 0.05 for residents. Intraclass correlation coefficient values were 0.2 for all observers, 0.18 for dermatopathologists, 0.33 for general pathologists and 0.15 for residents. CONCLUSIONS: Histopathological grading for dysplastic nevi was not reproducible in this Brazilian series, so the criteria used are not a helpful histopathological parameter for clinicopathological correlation.