Intra-operative procedures to localize endocrine tumours of the pancreas and duodenum.

Somatostatin receptor scintigraphy is the best imaging method to identify the presence of neuroendocrine gastroenteropancreatic tumours. Nevertheless, a well structured surgical approach incorporating specific intra-operative methods can localize those tumours that cannot be readily detected by this imaging technique. In the case of gastrinoma, standard palpation allows duodenal tumour detection in approximately 60% of cases, endoscopic transillumination, in more than 80%. Furthermore, adding duodenotomy, 95-97% duodenal tumours can be localized. Intraoperative ultrasound, instead, does not add much to standard palpation in duodenal gastrinoma localization. For insulinoma detection, among the intra-operative methods, inspection gives the poorest results, identifying the lesion in only 20% of cases. Palpation offers better results, localizing 60-80% of insulinomas. The introduction of intra-operative ultrasound has revolutionized the ability to find pancreatic insulinoma, allowing the surgeon to identify the insulinoma in nearly every patient.