Evaluation of proliferation activity of oral lichen planus and oral lichenoid reactions using quantitative and qualitative analysis of AgNORs (Argyrophilic Nucleolar Organizer Regions)

Bachground & Aims: Oral lichenoid reactions (OLR) and oral lichen planus (OLP) are clinically and histopathologically similar but their therapeutic approach are different. Due to the presence of dysplasia in oral lichen planus which effects prognosis, the aim of study was the evaluation of proliferation activity of OLPs and OLRs and their subtypes. AgNOR technique that is inexpensive and easy to perform was used to differentiate OLPs and OLRs and their subtypes. Materials & Methods: in this cross sectional , retrospective study, samples consisted of 45 OLPs, 30 OLRs 15 normal oral mucosa (N) from healthy persons (as control group). The samples were stained by AgNOR technique. AgNOR dots were counted on 100 cells from basal and para basal layer . The mean AgNOR dost per nucleus were calculated. Proliferation index (number of cells with AgNOR dots≥ 5) was also determined. Variation in size of AgNOR dots was categorized into 2 groups. Result: There were significant differences between OLP(and its subtypes) and N and also between OLR(and erosive type) and N . Such a difference was also between reticular OLP and reticular OLR.with regard to AgNOR count. Conclusion: Since reticular OLP had significantly higher AgNOR count than reticular OLR in our study, we can suggest the use of AgNOR technique for differentiation of reticular type of OLP from OLR on challenging histopathologic cases.