Imaging of pancreatic neuroendocrine tumors: Update, classification and state-of-the-art review

Pancreatic neuroendocrine tumor (panNENs) is the second most common pancreatic cancer after ductal adenocarcinoma (8–10% of all pancreatic tumors). PanNENs represent a heterogeneous group of tumors both clinically, due to their specificity to be functional or non-functional, and prognostically and histopathologically, ranging from benign (well-differentiated) to highly aggressive forms (neuroendocrine carcinomas) with a prognosis comparable to that of adenocarcinoma. All panNENs should be classified according to the WHO 2022 classification and AJCC TNM 2024 classification. Imaging plays a major role in diagnosis of the primary tumor, its characterization and determination of prognosis, local and distant extension assessment, diagnosis of tumor predisposition syndrome, and post therapeutic evaluation. Imaging of panNENs is extremely rich, combining morphological imaging techniques (ultrasound, CT, MRI), endoscopic exploration techniques and nuclear medicine imaging techniques using radioactive tracers.