Inflammation and Stromal Alterations–Histopathological Assessment of Invasive Changes in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma is often diagnosed at advanced stages with inflammation and stromal remodeling considered important early events. Our study evaluated eosinophil infiltration and collagen fiber characteristics in oral epithelial dysplasia, early invasive carcinoma and oral squamous cell carcinoma using special histochemical stains, to assess their histopathological significance.

In this retrospective observational study, 67 archival tissue samples comprising 25 oral squamous cell carcinoma, 25 oral epithelial dysplasia, and 17 early invasive carcinoma cases were analysed. Congo red stain was used for eosinophil assessment, while Picrosirius red under polarized microscopy was used to evaluate collagen characteristics.

Total eosinophil count increased significantly from oral epithelial dysplasia to early invasive carcinoma to oral squamous cell carcinoma (p < 0.001). Collagen fibers displayed a significant shift in polarizing color, from reddish-orange in oral epithelial dysplasia and early invasive carcinoma to greenish-yellow in oral squamous cell carcinoma (p < 0.001). Total eosinophil count showed a significant negative correlation with the polarizing color of collagen fibers (p < 0.001).

The findings suggest associated inflammatory and stromal alterations during oral carcinogenesis. Special histochemical stains may provide supportive information during routine histopathological assessment.