Histopathology of preneoplastic and neoplastic lesions of the esophagus in BUF rats ingesting diethylnitrosamine.

Carcinomas developed in the mucosa of the esophagus in BUF strain rats ingesting diethylnitrosamine in the diet. The stages of hyperplasia, hyperplastic nodules, small carcinomas, and large, well-developed carcinomas were observed. Carcinomas, which were well differentiated, poorly differentiated, or undifferentiated, invaded the adjacent tissue but did not metastasize.