Pancreatic Surgery.

Pancreatic neuroendocrine tumors (pNETs) are rare and clinically demanding diseases. They are clinically defined as functioning or nonfunctioning depending on the presence of a syndrome related to inappropriate hormone secretion. Functioning pNETs are often small in size and localization may be difficult also due to their possible extraduodenal-pancreatic origin in the jejunum, stomach, mesentery, spleen and ovaries. The improvement and the widespread use of cross-sectional imaging techniques has significantly increased the detection of small, nonfunctioning pNETs. The European Neuroendocrine Tumor Society (ENETS) guidelines now suggest a 'wait and see' policy for these small, incidentally discovered tumors, which are smaller than 2 cm. On the other hand, surgery still always represents the treatment of choice for pNETs >2 cm and/or for symptoms. A large proportion of patients with pNETs have locally advanced disease at diagnosis. Radical surgery of pNETs includes both typical and atypical pancreatic resections. At diagnosis, between 25 and 93% of patients with pNETs have synchronous neuroendocrine tumor liver metastases. Radical resection of the primary tumor, associated with complete, eventually multistep, resection of the liver metastases, can be considered in selected cases. In recent years minimally invasive approaches, either laparoscopic or robotic, have played an increasing role in the treatment of pNETs.