Knowing the unknown in oral squamous cell carcinoma: An observational study

Introduction: Conventional oral squamous cell carcinoma (OSCC) is relatively easy to diagnose on histopathology, as it comprises dysplastic epithelial cells with variable degrees of squamous differentiation. Different grading systems have been employed in grading OSCC based on its dysplastic features and host response. Some unusual features such as clear cell change, epithelial–mesenchymal transition (EMT), stromal hyalinization, stromal desmoplasia, perineural invasion, vascular invasion, tissue eosinophilia, giant cells, and tertiary lymphoid follicle formation are evident in OSCC histologically but have not yet been accounted in any grading systems of OSCC except perineural and vascular invasion. Aim: The aim of the present study was to identify these uncommon features and to correlate them with different grades of OSCC. Materials and Methods:This study was conducted on 100 histopathologically confirmed OSCC cases retrieved from the archives of our department. They were graded on the basis of Broder's grading system and were reviewed for the features mentioned above. Data collected were subjected to statistical analysis. Results: Clear cell change, EMT, foreign body giant cells, and tumor giant cells were observed in 13%, 20%, 1%, and 3% of cases, respectively. We found stromal desmoplasia in 15% and stromal hyalinization in 9% of cases. Tissue eosinophilia, tertiary lymphoid follicle formation, and perineural invasion were observed in 12%, 3%, and 2% of cases, respectively. Vascular invasion was not evident in any of the cases examined. Conclusion: The incidence of the unusual features was 7.8% in our study.