Diagnostic Prediction of Pancreatic Masses

The goal of this observational study is to learn if a strategy can be developed for differentiating autoimmune pancreatitis (AIP) and primary pancreatic lymphoma (PPL) from pancreatic ductal adenocarcinoma (PDAC) in patients presenting with pancreatic masses. The main question it aims to answer is: What features, in the perspectives of clinical manifestation, laboratory tests, and imaging, can differentiate different kinds of pancreatic masses (AIP, PPL and PDAC)? Participants will not be given any interventions since this is a retrospective observational study.