Carcinoma of the right colon: a change in characteristic configuration?

Carcinoma of the colon occurring to the right of the middle colic vessels is usually described as morphologically and clinically distinctive from cancers occurring in the left colon. Cancers of the right colon are characterized as polypoid tumors that are discovered in the search for occult blood loss, whereas carcinomas of the left and sigmoid colon are described as scirrhous and often annular in configuration, giving rise to obstruction as the characteristic clinical presentation. A personal experience with constricting annular lesions of the right colon that were considered atypical has led to a review of the total experience in colonic resections for cancer (excluding abdominoperineal resections for carcinoma of the rectum) at one metropolitan university medical center. Of 152 colonic resections for cancer within 39-month interval, 57 resections were for cancer of the right colon and 95 for cancer of the left colon. One half of the cancers of the right colon were annular, whereas only one third of those of the left colon were so described by operative, pathologic, and radiologic criteria. Differences in clinical presentation of cancers of the right and left colon are probably attributable more to the form and function of the colon in each anatomic region than to any characteristic configuration of the tumor itself.