Histological and Clinical Characteristics of Oral Squamous Cell Carcinoma Analyzed by Digitally Assembled Whole-Mount Sections

Background: The diagnosis of oral squamous cell carcinoma (OSqCC) is sometimes delayed. In this study, we attempted to comprehensively analyze the surface and cross section of OSqCC using whole-mount sections. Methods: Representative cross sections of 41 pT2 and pT3 OSqCC were digitally assembled, and whole-mount sections were reconstructed. In the cross section of the tumor, the degree of differentiation was classified as well/moderately differentiated (WDMD) and poorly differentiated (PD); and the surface of the specimen was divided into four types: benign-looking epithelium, dysplasia, carcinoma, and ulceration. Results: In the cross-sectional analysis, 17 cases (41.5%) consisted of only WDMD, and the PD component was predominant in seven cases (17.1%). In the remaining 17 patients, the PD component was partial (< 50%). When grouping noncancerous lesions (benign-looking epithelium and dysplasia, BnDy) and cancerous lesions (carcinoma and ulceration, CaUl) in the surface analysis, the proportion of CaUl was significantly lower in the tongue than in other oral sites (p = 0.009) In the survival analysis, although not statistically significant, the overall survival of partial PD patients was more similar to that of the predominant PD group compared to that of the WDMD-only group.