Lichen Planus of the Lip—Case Series and Review of the Literature

Background and Objectives: Lichen planus of the lip (LPL) is a chronic inflammatory condition that resembles actinic cheilitis, discoid lupus erythematosus, graft-versus-host disease, and lichenoid reaction to dental materials or drugs. The purpose of this study was to conduct a literature review on lichen planus lip involvement and to report a retrospective observational study that characterises and explores the clinical, histopathological, and evolution of the lesions in a group of patients with unique involvement of LPL. Materials and Methods: Clinical data of patients diagnosed with LPL was retrieved from the medical charts of the patients referred to the Oral Pathology Department of the “Carol Davila” University of Medicine and Pharmacy. A concurrent electronic literature research was carried out using PubMed and Web of Science from 2003 to 2023. Results: Eleven patients diagnosed with unique LPL were analysed (male/female ratio was 1.75, mean age 63.64 years ± 12.52). All patients presented lesions of the lower lip; the clinical forms were atrophic (six cases) and erosive (five cases), and the histopathological exam confirmed the diagnosis. After topical treatment with corticosteroids, most of the patients had complete remission. The literature review revealed 24 studies (sixteen case reports and eight case series) which comprised 84 patients. Isolated lip involvement was reported in 17 studies, and five articles with concomitant oral lichen planus, while two articles did not mention this criterion. Conclusions: Our study brings new data on isolated lichen planus of the lip that primarily affects the lower lip with predominance in male patients. It was reported worldwide in patients between 22 and 75 years old. Topical corticosteroids were the main treatment prescribed and they usually brought remission of the lesions. Lichen planus of the lip is a challenging diagnosis for oral health practitioner providers as well as for dermatologists.