Oral lichen planus (OLP) is a disease with unclear etiology or pathogenesis, categorized by the World Health Organization as oral lichenoid lesions (OLL; interface mucositis or lichenoid mucositis) into a group of potentially malignant disorders. The diagnosis of OLP is challenging because the clinical and histopathologic features are frequently seen in OLP, OLL and/or other mucosal diseases with lichenoid characteristics. Furthermore, OLP has a dynamic nature. Finally, an early and precise diagnosis can play a decisive role, allowing timely treatment and thus improving the patient quality of life. This article summarizes the state-of-the-art regarding OLP and OLL and discusses the challenges faced on making an accurate diagnosis, aiming to provide a practical guideline for the postgraduates and oral physicians in reaching the diagnosis of these lesions.
Keywords: Diagnosis guideline; Lichen planus; Oral lichen planus; Oral lichenoid lesions; Precancerous conditions.