Localization of neuroendocrine tumors of the pancreas

The diagnosis of neuroendocrine tumors of the pancreas is based on clinical, biochemical, and ultrastructural data. The different radiological modalities are employed only for localization, except in the case of nonfunctioning neoplasms, for which a differential diagnosis from adenocarcinoma can be suggested based on the radiographic images. Generally, the initial evaluation should consist of the noninvasive studies and should be complemented by angiography and, in cases of functioning neoplasms, with pancreatic venous sampling if the preliminary findings are inconclusive. However, the localizing work-up should be terminated when the information obtained is sufficient to determine the therapy that will follow. If the ultrasonic or computed tomographic findings preclude surgical resection, further work-up is obviously unnecessary.