Abstract
The adenomatous lesions, which could be benign or malignant, have been described in the duodenum and along the duodenal ampulla in individuals with familial adenomatous polyposis (FAP) post-colectomy, along with other extracolonic manifestations. To our best knowledge, we present a unique case of the involvement of the accessory duodenal ampulla in a patient who had undergone colectomy with ileorectal anastomosis with an established diagnosis of FAP. During the endoscopic examination, the patient was found to have adenomatous growth in the accessory duodenal ampulla, which was successfully removed via endoscopic retrograde cholangiopancreatography (ERCP). To prevent pancreatitis, a temporary plastic stent was inserted and successfully removed three weeks later.