Evaluation of tumor-associated tissue eosinophilia in different stages of oral squamous cell carcinoma using special stains: An in vitro histopathological study

Abstract

Aim: To evaluate the tissue eosinophilia in different stages and grades of oral squamous cell carcinoma (OSCC) and correlate its possible role as a prognosticator in primary OSCC using special stains like Congo red and carbol chromotrope. Materials and methods: Forty-five intraoral histopathologically proven cases of OSCC were selected (15 cases each of well-differentiated squamous cell carcinoma (WDSCC), moderately differentiated squamous cell carcinoma (MDSCC), and poorly differentiated squamous cell carcinoma (PDSCC)). Three sections of 4 μm were taken for each case. All slides were stained using routine stain, i.e., hematoxylin and eosin (H&E), and special stains, i.e., carbol chromotrope and Congo red respectively, for studying tissue eosinophils in all these groups. Histopathological evaluation was performed on paraffin sections for calculating the quantitative eosinophil distribution by two separate observers who were blinded to clinical and histopathological data. Tumor-associated tissue eosinophilia (TATE) was calculated using the density method. Results: An increase in the degree of TATE from stage I to stage IV suggested that elevated tissue eosinophilia was seen with an increasing size of primary tumor. Also an increase in TATE was observed with an increasing grade of OSCC. Chromotrope stain was found to be a much better and more specific stain for eosinophils, and gave more accurate eosinophil count compared with H&E and Congo red. Conclusion: The findings of the present study highlight the significance of eosinophil counting and that it can be used as an additional morphological parameter in the grading of OSCC which can also be included in the biopsy report.