ABSTRACT
Pancreatic endocrine tumors (PET) are rare neoplasms of the pancreas accounting for less than 5% of all primary pancreatic malignancies. Insulinomas, gastrinomas, glucagonomas and somatostatinomas is included in PET. PETs are usually classified into functioning and non-functioning tumors and presents with a range of benignity or malignancy. It is very important to accurate diagnose the PET location and to predict the benignity or malignancy of PET in terms of the treatment strategy, because PET have higher respectability, better response to chemotherapy and better prognosis compared to that of pancreatic adenocarcinoma. The utility and reliability of different imaging modalities depends on the characteristics of PETs, specifically their size. Functioning PET tend to be small (less than 2 cm), well circumscribed, homogeneous, and usually shown as strong enhancement on contrast enhanced CT or MR imaging. Non-functioning PET tend to be larger (4~10 cm), heterogeneous, and may contain the cystic areas of degeneration and necrosis. In this article, we present the various imaging findings of PET according to recent WHO classification.