Endoscopic ultrasound in the localisation of pancreatic islet cell tumours

The role of endoscopic ultrasound (EUS) in the evaluation of entero-pancreatic endocrine tumours has evolved in conjunction with advances in other imaging methods. The high spatial resolution of this technique allows the detection of very small lesions and their precise anatomical localisation. In patients with biochemically proven insulinoma, EUS can be effectively used as a first line investigation, with a sensitivity of 94%. Combined with thin section CT the sensitivity rises to 100%. There is also high sensitivity in diagnosing intrapancreatic gastrinomas but lower for those arising in the duodenal wall which require detailed duodenal evaluation at surgery. EUS in conjunction with Somatostatin Receptor Scanning (SRS) has a combined sensitivity of 93% for gastrinomas. EUS is recommended for screening of asymptomatic patients with genetically proven MEN1. There is a limited role for EUS guided biopsy in pancreatic endocrine tumours.