The value of push-type jejunal endoscopy in familial adenomatosis coli/Gardner's syndrome. Push-type jejunal endoscopy using a long forward-viewing duodenofiberscope was performed in 10 patients with familial adenomatosis coli/Gardner's syndrome. Jejunal polypoid lesions were detected in nine of the 10 patients (90%). The lesions appeared sessile, whitish, and measured 3 mm or less in diameter. Histologic findings of the biopsy specimens from these polypoid lesions revealed tubular adenoma in all nine patients. In addition, this method led to the detection of duodenal adenomas in one patient, in whom duodenofiberscopy with the side-viewing instrument revealed no polypoid lesions in the bulb and second portion of the duodenum. In view of these results, we recommend that push-type jejunal endoscopy, as well as side-viewing duodenofiberscopy, should be added to the usual preoperative examinations done in patients with this disease. 