Nickan Research Institute Immunopathologia Persa 2423-8015 8 1 2022 01 01 Evaluation of mast cell count in oral and cutaneous lichen planus lesions e3 e3 10.34172/ipp.2022.03 EN Mohammad Koochak Dezfouli https://orcid.org/0000-0002-4933-8200 Fatemeh Montazer https://orcid.org/0000-0002-4487-1399 Atena Shiva https://orcid.org/0000-0002-0584-1859 Mahmood Moosazadeh https://orcid.org/0000-0002-5452-514X Maryam Biglari Abhari https://orcid.org/0000-0002-9009-0593 Hadi Alidoust https://orcid.org/0000-0001-6798-2393 Maryam Zamanzadeh https://orcid.org/0000-0002-8825-2645 Journal Article 10.34172/ipp.2022.03 2021 01 24 2021 03 24 Introduction: Lichen planus (LP) is a relatively common chronic mucocutaneous disorder diagnosed based on clinical manifestations and histopathological findings. Mast cells (MCs) are multifunctional immune cells that are involved in the pathogenesis of LP by releasing certain chemical mediators. Objectives: The purpose of this comparative study was to estimate the number of intact (granulated), degranulated and total MCs in oral lichen planus (OLP) and cutaneous lichen planus (CLP) lesions. Patients and Methods: The present descriptive-analytical and cross-sectional study was conducted on 125 LP blocks, including 40 OLP samples and 85 CLP samples. The mean number of granulated, degranulated and total MCs were counted under light microscope (×100 and ×400). Data were analyzed by SPSS version 24 software using Mann-Whitney U and Pearson’s chi-square tests. Results: The mean total MC count was 14.92 ± 3.90 in OLP samples and 14.04 ± 5.60 in CLP samples respectively which was not statistically significant. The mean granulated MC count in CLP (10.53 ± 5.70) was higher than in OLP (4.34 ± 3.46) (P<0.001). The mean degranulated MC count in OLP (10.57 ± 2.99) was higher than in CLP (3.51 ± 2.72) (P<0.001). Conclusion: No statistically significant difference was observed in the total MC count between OLP and CLP; however the difference in the degranulated MC count was detected between OLP and CLP. Despite the homogeneity in the total MC count, the MCs appear to play different pathological roles in OLP and CLP.