Malignant Transformation in Oral Lichen Planus and Oral Lichenoid Lesions: A Retrospective Study.

Abstract

The goal was to determine the incidence and risk factors of malignant transformation of oral lichen planus (OLP); oral lichenoid lesions without (OLL) or oral dysplasia with lichenoid features (ODLF). We identified a retrospective cohort of 188 patients with a pathological diagnosis of OLP, OLL, or ODLF, and a minimal 12-month follow-up. In each subgroup, we analyzed the rate of malignant transformation and performed a uni- and multivariate analysis of factors associated with malignant transformation. Diagnoses of OLL, OLP, and ODLF were made in 80.9%, 15.4%, and 3.7% of patients, respectively. The average follow-up was 51.5 months. The malignant transformation rates for OLL, OLP, and ODLF were 5.9% (n = 9), 0% (n = 0), and 42.9% (n = 3), respectively. Multivariate analysis performed on the entire cohort showed that the presence of dysplasia was significantly associated with transformation to OSCC (OR = 7.40; p = 0.01) as well as the asymmetry of lesion (OR = 8.81; p = 0.009), whereas there was a trend toward an association between plaque-like lesions and malignant transformation (p = 0.07). The risk of malignant transformation was only observed in OLL and ODLF. The presence of dysplasia is associated with a higher risk of malignant transformation. Clinical and histological diagnosis of plaque-like OLP is challenging, highlighting the need for future genomic investigations to enable a better molecular characterization of this condition.