A Case of Adenoacanthoma of the Rectosigmoid

This is the authors' abstract. We don't add key points for this paper.

A 58-year-old male patient, who had adenoacanthoma of the rectosigmoid, was examined, and the case is reported in the light of the related literature. Our literature search revealed 23 cases of adenoacanthoma in the colon except for the lower rectum in Japan and 38 cases in foreign countries. Adenoacantohma showed a tendency to occur frequently in deep areas of the colon such as the cecum and the ascending colon, in contrast to colic adenocarcinoma, resulting in a relationship with the size of tumors. Right hemicolic adenocarcinoma is often discovered at a relatively advanced stage and tends to become large so as to produce squamatization, indirectly suggesting a theory of squamatization of adenocarcinoma. Histologic examination led us to the consideration that the occurrence of the tumor in our case could be most reasonably explained by this theory. With respect to diagnosis, there have been no reports indicating that preoperative diagnosis of adenoacanthoma is possible, and this was confirmed with postoperative histopathological diagnosis. As for therapy, surgical excision similar to that in cases of colic adenocarcinoma is in the first choice. As for prognosis, investigation of Japanese cases with descriptions on degrees of progression suggested that the prognosis is not as poor as the conventional notion.