The authors report on twelve cases of non-ampullary duodenal neoplasm and remark the rarity of this pathology. According to the literature, the traditional endoscopy is the mainstay diagnostic test, because of aspecific digestive symptoms, but the authors stress the importance of the "longue" endoscopy or endoscopy integrated with duodenography in non-responders patients who had non-diagnostic traditional endoscopy for neoplasm. Duodeno-cephalo-pancreatectomy and segmentary duodenal resection are proposed by tumor site. Better results for prognosis can be obtained only with an early diagnosis and radical surgical therapy, because of chemotherapy and radiotherapy don't improve survival.