Evaluation of Fibrotic Changes in OSMF:A Retrospective Study Using Special Stains and Polarizing Microscopy

Background: Oral submucous fibrosis (OSMF), a potentially malignant oral disorder has the highest rate of malignant transformation of about 7-13%. The connective tissue changes that occur in this disease are characteristic and are stained with special stains. Objective: The study was done to compare common and special stains under light microscopy and polarizing microscopy to evaluate the levels of fibrosis in oral submucous fibrosis and assess the type of collagen present in the stromal area. Materials and Methods: Fifty tissue blocks were selected from the archives and were prepared and stained with H&E, Masson's trichrome, Van Gieson and Picrosirius red and studied under light microscope and polarizing microscope respectively. Results: H and E stained slides were useful in diagnosing the lesion but was not able to highlight the level of fibrosis. Masson's trichrome and Van Gieson stained slides showed the depth of the lesion which extended even to the deeper muscle layer. The type of collagen present was definitively seen by the birefringence in polarizing microscopic study. Interobserver variation was less and all the values regarding the effectiveness of the special stains in detecting the level of fibrosis were statistically significant. Conclusion: Special stains can be used routinely in laboratories to demonstrate connective tissue lesions especially in cases of OSMF. Depth of the lesion and the area of involvement help in treatment planning to be delivered. Large scale studies with more categories and inclusion criteria are required along with the special stains to assess the other alterations in OSMF.