Epithelial lesions antedating oesophageal carcinoma. I. Histologic study in mice.

The histological changes occurring in the oesophageal mucosa after protracted topical treatment with diethylnitrosamine was investigated in 87 C57B1 mice. The histological changes were classified into slight, moderate, severe dysplasia, carcinoma in situ, questionable invasive carcinoma and invasive carcinoma. Starting from moderate dysplasia, the epithelial-stroma border became irregular with formation of buds bulging into the stroma. Similar histological changes have been found in the same strain of animals during carcinogenesis of the cervix uteri, another organ covered by squamous epithelium. The findings strongly suggest an association between the degree of cellular atypia, the formation of epithelial buds and progression towards invasive carcinoma.