ABSTRACT
The field of gastroenteropancreatic (GEP) neuroendocrine neoplasms (NEN) has evolved rapidly over the past decade and this has helped to enhance and understand the epidemiology, genetics, presenting features, and diagnostic capabilities and therapeutics. Most GEP-NENs are sporadic, but they can be multiple and part of a familial syndrome such as multiple endocrine neoplasia type 1 (MEN1), von Hippel-Lindau (VHL) syndrome, and neurofibromatosis type 1 (NF1). Clinical presentation depends on the site of the primary tumor and whether they are so-called functioning tumors, that is, whether the peptides secreted produce symptoms. GEP-NENs can be integrated in several genetic syndromes, such as MEN1, VHL syndrome, and NF1. Upper gastrointestinal endoscopy is essential for the detection and characterization of NENs up to the angle of Treitz. Ileo-colonoscopy allows the diagnosis of rectal, colonic, and very occasionally distal ileal lesions. With the exception of small gastric and rectal NENs, the use of cross-sectional imaging is almost systematic in the management of GEP-NENs.
