[Hyperplastic changes in the mucosa in colon cancer]

67 segments of rectum and sigmoid removed surgically because of carcinoma were examined: the surface of intestinal mucosa stained with methylene-blue was studied in order to determine the number and localization of focal changes in the macroscopically unchanged areas. Colon microscopy was performed clinically in 24 patients with carcinoma of the rectum and in 24 control individuals. 28 hyperplastic polyps and 1037 microscopic hyperplastic foci were found in operative material. An active metabolism is established by means of electron autoradiography in the cells of hyperplastic focus. Areas of dysplastic epithelium were rarely found in big hyperplastic polyps. Areas of diffuse hyperplasia (transitional mucosa) with crypt deepening and presence of a high number of goblet cells were found near tumour. A certain role of hyperplastic processes in carcinogenesis is forwarded. Numerous microscopic changes in the mucosa epithelium may testify against the carcinoma development de novo.