Morphogenesis of human colonic cancer.

A total of 155 early carcinomas, collected from colonoscopic polypectomy cases, surgically removed specimens, and resected colon from patients with adenomatosis coli, were histologically investigated in order to find their characteristic morphologic features. The commonest types of early carcinomas examined had a short stalk or were broad-based, and carcinomas 1 to 2 cm in diameter were the largest in actual number, although the malignancy rate increased with increasing size. The malignancy rate of small adenomas, under 1 cm in diameter, is higher than previously estimated. The clinical importance of the shape and size of such polyps is stressed for earlier detection of carcinomas of the colon, and an improved concept of the morphogenesis of colonic carcinoma is proposed.