CLINICAL STUDY Pitfalls in endosonographic imaging of suspected insulinomas: pancreatic nodules of unknown dignity

Objective: Endosonography enables localization and characterization of gastroenteropancreatic neuroendocrine tumors. We have studied the problem of misleading abnormalities of pancreatic morphology as obtained by endosonographic imaging. Design and methods: A total of 438 endosonographies performed for known or suspected diseases of the adrenal glands and/or the pancreas and/or suspected metastases in the neighboring tissues were analyzed. Results: In the pancreas, nine benign insulinomas, four non-metastatic islet cell carcinomas, and multiple benign neuroendocrine tumors in one patient with multiple-endocrine neoplasia-1 (MEN-1) disease were detected and correctly localized as proven by postoperative histology. In three further patients with genetic diagnosis of MEN-1, asymptomatic tumors were detected and are under observation. However, we also found an 8 £ 4 mm hypoechoic tumor in the cauda pancrea-tis of a patient with severe factitial hypoglycemia (glimepiride). In another patient suffering from severe hypoglycemia, a hypoechoic area of 24 £ 10 mm in the processus uncinatus/caput pancreatis was found. Although organic hyperinsulinism was excluded, this patient underwent surgery becaus