Intramucosal duodenal adenocarcinoma concomitant with Saint's triad

Duodenal tubulovillous adenomas are rare and have malignant potential. Their successful management depends on the preoperative diagnosis and adequate excision. Endoscopic mucosal resection or submucosal dissection can control superficial tumors. Adenocarcinoma of the duodenum may originate in tubular or tubulovillous adenoma, and possible diagnostic challenges occur concerning the endoscopic biopsy findings. We report a 62-year-old female with chronic epigastric burning and a bolus sensation. Upper gastrointestinal endoscopy showed a non-ampullary duodenal tumor, and the biopsy study diagnosed a tubulovillous adenoma. Further mucosectomy revealed an intramucosal adenocarcinoma in a tubulovillous adenoma with a tumor-free pedicle. Besides the intestinal neoplasms, the patient had the diagnosis of classical Saint's triad; and the manifestations were hiatus hernia, gallbladder disorder, and colonic diverticula. The objective is to report two scarcely described conditions and comment on controversial points of view about the concomitance of Saint's triad and malignancy. Case reports can reduce late diagnosis, enhancing the suspicion index on rare diseases.