Study of Villous Adenoma of Large Intestine-Morphological Characteristics and Vascular Structure Image

In order to more fully understand the morphological chracteristics and the process of morphologic changes of villous adenoma of the large intestine, the vascular structure images of eleven surgical resection specimens were microangiographically studied. Macroscopically, villous adenomas were pedunculated polyps and nodular conglomerate-like lesions. Pedunculated villous adenomas had numerous large stalk vessels, suggesting abundant blood flow. By imaging the nodular conglomerate-like lesions composed of a conglomerate of polyps with stalk vessels, destruction/deciduation and ulceration of individual polyps were found. Vascular structures similar to the mucosa of normal colon were found at the periphery of polyps. In lesions with cancer invaded to the proper muscle layer, scattered ulcerations due to the destruction of polyps were also observed, corresponding to a Dukes B lesion. Invasive carcinomas were characterized by the basic vascular patterns of villous adenoma. Protuberant villous adenocarcinoma showed vascular structures similar to pedunculated polyp. Ulcerative villous adenocarcinoma had polypoid remnants with a vi llous component at the periphery of the tumor. Stalk invasion seems to play an important role in ulceration. The above findigs are considered very important additional information regarding the development of villous ademoma, as well as for endoscopic treatment or local excision for the prevention of hemorrhagic comlications of incomlete removal of adenoma.