Dysplastic change rate in cases of oral lichen planus: A retrospective study of 112 cases in an Iranian population

Backgrounds: Lichen planus is a chronic systemic disease and oral mucosa is commonly involved. Oral lichen planus (OLP) most commonly affects middle-aged women. The prevalence of the disease ranges between 0.5% and 2.6% in the general population and the range of malignant transformation varies between 0% and 10%. Objectives: To assess the rate of malignant transformation of OLP samples. Materials and Methods: This retrospective study was carried out on 112 medical records of patients with histological diagnosis of OLP who attended the Department of Pathology at the Educational Hospital from 2005 to 2012. H&E-stained slides were reviewed by two pathologists using strict clinical and histopathological diagnostic World Health Organization (WHO) criteria. Dysplastic changes were diagnosed and graded according to the latest WHO classification. Results: Of the 112 cases diagnosed as OLP, there were 39 males and 73 females and the patients′ ages ranged from 15 to 86 years (mean age 44.5 years). The erosive form with fifty cases was the most common clinical type and the papular type with one case was the least common clinical type. Regarding the site, the buccal mucosa was the most common site with 52 cases. Totally, dysplastic changes were found in 12 samples, among them five cases showed mild dysplasia and seven cases showed moderate dysplasia. One case developed oral squamous cell carcinoma after 3 years. Conclusion: OLP is considered as a premalignant condition by the WHO and several authors. Although the malignancy rate is not so high, to reduce morbidity and mortality from cancer arising on OLP lesions, a regular follow-up examination is recommended.