Histological cartography of the tumor microenvironment: Mapping stromal and inflammatory zones in head-and-neck squamous cell carcinoma by Yamamoto–Kohama system

Objectives: The objective of the study is to evaluate desmoplastic stromal reaction patterns and peri-tumoral inflammatory infiltrate with the various histopathological parameters, including histological grade, worst pattern of invasion (WPOI), depth of invasion (DOI), YK grade, perineural and lymphovascular invasion (LVI). Materials and Methods: This retrospective observational study included 160 cases of HNSCC. Clinical data were extracted from case records. Two pathologists separately examined archived hematoxylin and eosin-stained sections for histopathological parameters. Statistical analysis: Data were analyzed using the Statistical Packages of the Social Sciences (SPSS) version 22.0 (IBM SPSS Statistics, Somers, NY, USA). The Chi-square or Fisher’s exact test was used for statistical analysis; p <0.05 was considered significant. Results: In well-differentiated HNSCC, mature stromal response was prevalent and significantly correlated with grade, stage, WPOI, DOI, LVI, YK classification (all p <0.01), and perineural invasion (PNI) ( p = 0.02). Peritumoral inflammatory infiltrate correlated with stromal type, stage, WPOI, DOI, and YK classification (all p <0.01). YK classification showed significant associations with stromal type, grade, stage, DOI, WPOI, PNI, and LVI (all p <0.01). Conclusions: The significant association between stromal characteristics, peritumoral inflammatory response, and YK classification with established prognostic parameters highlights their potential value in prognosis and risk stratification.