RESUMO
Abstract Objective To report the prevalence of malignant transformation of vulvar lichen sclerosus (VLS) and possible risk factors. Methods This is a cohort study with data analysis from medical records of 138 patients with histological diagnosis of VLS registered at the Vulvar Pathology Outpatient Clinic of the University Hospital, between 2007 and 2017. Predominance of risk factors was performed using logistic regression analysis. The variables studied were the length of follow-up, age, regular or irregular follow up; presence of symptoms (dyspareunia, pruritus and/or vulvar burning); histology characteristics, the presence of epithelial hyperplasia; and the presence of autoimmune diseases. Results There were 138 patients included in the study, and among them five progressed to malignant transformation. The patients had a median age of 59 years and 83% were symptomatic. The most frequent symptom was itching with 72%. Autoimmune diseases were present in 11.6%, the most prevalent being thyroid disease. All five case of malignant transformation (0.6%) had an irregular follow up. The logistic regression analysis was used among the studied variables, and no statistical significance was found among them (p ≥ 0.05). The relationship between hyperplasia and the clinical outcome of malignant transformation, in which non-significant but acceptable p value close to 0.05 was observed. Conclusion The prevalence of malignant transformation in patients with VLS was 0.6%, and common factors were the lack of adherence to medical treatments and the loss of follow-up.