Endoscopic ultrasonography in patients with gastrinomas.

Placing the endoscopic ultrasound transducer in the descending duodenum, the duodenal bulb and the stomach, all the pancreas can be imaged. Endoscopic ultrasonography is a sophisticated imaging technique able to accurately diagnose and localize primary endocrine tumours of the pancreas (mostly insulinoma and gastrinoma) which may not be detectable with other imaging modalities. Furthermore, endoscopic ultrasonography-guided fine needle aspiration allows cytology and/or biopsy specimens to be obtained, that are crucial for clinicians in decision making. In the case of extrapancreatic endocrine tumours, which are often localized in the second and third part of the duodenum, endoscopic ultrasonography may have difficulty in localizing small and flat lesions. In this case, the initial step would be identification of duodenal nodules by duodenoscopy and thereafter, a catheter echoprobe can be inserted to identify the extent of submucosal lesion. Then gastroduodenal nodules found by endoscopy and confirmed by endoscopic ultrasonography can be removed endoscopically using the technique of mucosectomy. In the case of large pancreatic lesions, endoscopic tattoo with dye-India ink or methylene blue may become helpful for the surgeon to perform local resection via duodenostomy.