直肠上部和乙状结肠下部浸润型腺癌。溃疡边缘有隆起的肿瘤块。会引起出血，可以通过粪便检查出来。右侧显示正常黏膜。肿瘤环绕结肠四周浸润肠壁。分期是根据浸润和破坏结肠的程度。
An encircling adenocarcinoma of the rectosigmoid region is seen here. There is a heaped up margin of tumor at each side with a central area of ulceration. This produces the bleeding that allows detection through a stool guaiac test. Normal mucosa appears at the right. The tumor encircles the colon and infiltrates into the wall. Staging is based upon the degree of invasion into and through the wall.
