Comparative studies on dysplasia of esophageal epithelium in four prefectures of Japan (Miyagi, Nara, Wakayama and Aomori) with reference to risk of carcinoma.

Distal two-thirds of the esophagus without macroscopically detectable malignant lesions from a total of 248 autopsy cases were examined for epithelial dysplasia on histological sections from serial blocks. The autopsy specimens had been obtained from Miyagi. Nara and Wakayama prefectures known for high incidence of esophageal carcinoma in Japan, and Aomori prefecture where the incidence of the disease is low. Epithelial dysplasia was classified into mild, moderate, and severe including carcinoma in situ according to the grade of epithelial atypism. Of 248 cases 91 (36.7%) had epithelial dysplasia and 30 (12.1%) had moderate and severe dysplasia. In one of the cases of severe dysplasia, in situ carcinoma was diagnosed. Lesions of dysplasia of the resected specimen were displayed in a diagram for the distribution of the abnormal epithelium. Cases of higher grade dysplasia tended more extensive in area and were slightly dominant in the distal third of the esophagus. Possible relationships of dysplasia with long-standing irritation to the esophagus and with precancerous lesions were discussed.