Malignant transformation of adenoma in large intestine--especially on villous adenoma.

The incidence of 454 resected adenomas was histologically 87.8% of tubular, 7.7% of tubulovillous and 4.5% of villous adenomas, respectively. Eigtosigmoid region. Male to female ratio was 1 to 1.8, 1.5 to 1 and 1.8 to 1 for the villious, tubulovillous and tubular adenomas, respectively. Adenocarcinomas of large intestine consisted of 684 cases, 709 lesions and male to female ratio was 1 to 1.01. It should be considered that the adenomas in female may grow largely compared with those in male, with subsequent malignant transformation. Although the adenomas were found at the rate of 26.4% in the rectosigmoid region, 74.2% of the adenocarcinomas were found in this region, because the adenomas in this region grow largely compared with the other regions. Mucinous carcinomas were found in 33%, 23% and 9%, respectively, in the adenocarcinomas with remaining adenoma showing villous, tuvulovillous and tubular types.