Neuroendocrine tumours of the duodenum and small bowel

Abstract

Abstract The incidence of duodenal (dNENs) and small bowel neuroendocrine neoplasms (SB-NENs) is growing. While dNENs are often discovered incidentally during upper gastrointestinal endoscopy, SB-NENs are frequently diagnosed in patients with carcinoid syndrome. The diagnostic workup for dNENs includes upper gastrointestinal endoscopy with biopsy, endoscopic ultrasound, and somatostatin receptor imaging, along with high-quality radiological examinations (computed tomography and/or magnetic resonance imaging) with contrast medium, that are also important for diagnosis and staging of SB-NENs. According to tumour size, depth of invasion, tumour location, and presence of nodal involvement, the management of localized dNENs ranges from conservative treatment (active surveillance or endoscopic resection) to surgical resection. In contrast, SB-NENs should be always treated with surgical resection of the primary tumour associated with lymphadenectomy, when technically feasible. If liver metastases are present and resectable, it is recommended to remove them as well. The overall prognosis of both dNENs and SB-NENs is good, with 5-year survival rates around 90% for localized dNENs and approximately 100% for stage I–II SB-NENs.