Concurrent colonic carcinoma and small-bowel carcinoid tumor. Case reports and review of the literature.

Recent reviews stressing the existence of synchronous and metachronous noncarcinoid neoplastic lesions in the same segment of an organ stimulated a review of experience with simultaneous small-bowel carcinoids and colonic carcinoma. Four cases of colonic malignancy associated with small-bowel carcinoid are presented. Included are cases with multiple carcinoids and concurrent multiple carcinomas; two metachronous carcinomas with subsequent ileal carcinoids, and three cases explored for colonic carcinoma with the discovery of incidental ileal carcinoids. There are few reports describing this variety of situations. The occurrence of concurrent malignant lesions, particularly more than one metachronous lesion in primary carcinoid cases, is uncommon.