Exploring the Controversy: Dysplasia in Oral Lichen Planus - A Comparative Study Based on WHO Criteria and the Binary System

Abstract Background To assess the presence and degree of epithelial dysplasia of epithelial dysplasia according to the World Health Organization (WHO) criteria and the binary system in oral lichen planus (OLP) and oral lichenoid lesions (OLL), and to compare the influence of individual architectural and cytological criteria on the assessment of the degree of epithelial dysplasia in these lesions. Methods Sixty-five biopsies from lesions diagnosed as OLP and OLL underwent evaluation by two oral pathologists to diagnose oral epithelial dysplasia. This assessment utilized both WHO criteria and the binary system, with consideration given to individual architectural and cytological criteria in the diagnostic process. Results All biopsies showed epithelial dysplasia, with the majority classified as mild epithelial dysplasia according to WHO criteria (73.8%) and low risk by the binary system (61.5%). There was a statistically significant association in the classification of epithelial dysplasia between WHO criteria and the binary system. No statistically significant differences were found in the association of the presence and degree of epithelial dysplasia with the diagnosis of OLP and LLO. Statistical analysis indicated that an increase in the number of mitotic figures was associated with the severity of epithelial dysplasia (moderate/severe) according to the WHO system. Drop-shaped projections of epithelial ridges, an increased number of mitotic figures, superficial mitoses, premature keratinization in single cells, abnormal variation in cell shape, and atypical mitotic figures were associated with the high risk by the binary system. Conclusion The presence of epithelial dysplasia is common in both oral lichen planus and oral lichenoid lesions, and the degree of epithelial dysplasia does not statistically differ between these lesions. The absence of epithelial dysplasia should not be considered a diagnostic criterion for classifying OLP. The binary system may provide a more precise assessment of epithelial dysplasia in OLP and LLO lesions.