Transitional mucosa in human colorectal lesions

Mucosa adjacent to colorectal disease was studied mucin-histochemically. Selected specimens were also studied immunohistochemically for carcinoembryonic antigen (CEA). Transitional mucosa, which showed elongation of crypts and marked sialomucin secretion, accompanied by a marked reduction in the normal sulfomucin content, was evident in 96 of 100 carcinomas (96 percent), 18 of 36 adenomas (50 percent), and 10 of 30 metaplastic polyps (33 percent). When considering the appearance of transitional mucosa, not only in the neoplastic lesions such as carcinoma or adenoma but also in the begin polyp, the transitional change adjacent to the carcinoma cannot be classified as a precancerous phenomenon; rather, it is a secondary one. The mucin-histochemical study disclosed transitional mucosa in all the 21 carcinomas less than 1 cm in diameter and immunohistochemical staining for CEA showed no remarkable change in the adjacent mucosa. Thus, it seems apparent that a change in mucous secretion precedes that of CEA expression in the mucosa adjacent to the carcinoma.