Unlike the stomach, the esophageal mucosal layer has abundant vessels. To study the histopathologic character of cancer of the esophagus in comparison with that of stomach, the histologic findings (such as vascular or lymphatic permeation and lymph nodal involvement of cancer) were surveyed in 52 lesions of superficial esophageal carcinoma in which carcinoma invasion was limited to the submucosal layer, 448 cases of so-called early gastric carcinoma in which the carcinoma invasion was limited to the submucosal layer, and 109 cases of gastric carcinoma invading the proper muscle layer (PM-carcinoma). With respect to lymph node metastasis and lymphatic and vascular permeation, there was a particularly high incidence of carcinoma extending to the submucosal layer (SM-carcinoma) of the esophagus and a similar high incidence of PM-carcinoma of the stomach. Carcinoma limited to the mucosal epithelium and mucosal layer of the esophagus (MM-carcinoma) has an incidence similar to carcinoma in the mucous membrane and SM-carcinoma of the stomach, respectively. Thus, the cases in which carcinoma invasion was limited to the muscle layer of the mucosa of the esophagus were shown to have a prognosis similar to that of so-called early carcinoma of the stomach.