Inclusion Criteria:  Patients with difficulty in distinguishing between FAIP and PC  Exclusion Criteria:  Referred patients with a history of having being conclusively diagnosed as AIP or PC; Patients with DAIP; Patients with alcoholic pancreatitis, hypertriglyceridemia pancreatitis or pancreatitis due to gallstones; Patients with pancreatic cystic tumors, pancreatic neuroendocrine tumors or solid pseudopapillary tumors of pancreas; Patients who cannot undergo EUS due to unsuitable conditions.