[Digestive system carcinoid tumor and synchronous malignant tumors].

270 digestive carcinoid tumors have been diagnosed at the Pathology Institute of Lausanne between 1971 and 1990; of these 21 were associated with other, synchronous, tumors: 7 of the carcinoids were from the appendix (33%), 8 from the small bowel (38%), 4 were from the colorectum (25%), one from the duodenum (4.5%) and finally one from the stomach (4.5%). Two thirds (14) were associated with adenocarcinomas of the colon, the rest with 2 gastric tumors, 1 tumor of the appendix, 1 of the gallbladder, 1 of the small gut, 1 of the duodenum and 1 of the peritoneum. The mean age of the patients was 70 years, which correlates with the large proportion of carcinomas of the colon. The males (16) clearly outnumbered the females (5) for no obvious reason. 80% of the carcinoids were discovered during the treatment of the associated tumor. Survival was directly related to the stage and aggressivity of the malignant tumor. The carcinoid itself hardly changed the prognosis, except for one case of liver failure due to metastases from carcinoid of the stomach associated with an adenocarcinoma. The histologic features of the carcinoid tumors were unexceptional. Different hypotheses to explain the associations are formulated.