Coexistence of intraepithelial carcinoma and glandular differentiation in esophageal squamous cell carcinoma

A review of 249 cases of squamous cell carcinoma of the esophagus showed 77 cases (30.9%) with intra‐epithelial carcinoma contiguous to the main lesion. There were 48 cases (19.3%) with glandular and/or mucus‐secreting components, in addition to the usual components of squamous cell carcinoma. Coexistence of intraepithelial carcinoma was observed in 20 cases (41.7%) among 48 with glandular differentiation, as compared with 57 cases (28.4%) without this differentiation. Of the 20 cases with glandular differentiation without preoperative irradiation, there were 16 (80.0%) containing areas of intraepithelial carcinoma. Moreover, among 77 cases with intraepithelial carcinoma, 20 (26.0%) were accompanied by glandular differentiation. Of nine tumors restricted to the mucosal or submucosal layer in 48 cases with glandular differentiation and in 44 of 203 cases without such differentiation, there were eight cases (88.9%) and 31 cases (70.5%) containing the areas of intraepithelial carcinoma, compared with rates of 30.8% and 16.6%, respectively, in the advanced carcinomas. Therefore, in the early carcinomas with glandular differentiation, there often coexist intraepithelial carcinomas. This high incidence of the coexistence of intraepithelial carcinoma and glandular differentiation, particularly in early cancers, supports the theory of a field carcinogenesis of esophageal carcinomas.