Focal Type 2 Autoimmune Pancreatitis Mimicking Pancreatic Cancer: Treatment with Neoadjuvant Chemotherapy and Surgery

A 51-year-old man was referred to our hospital for the further examination of main pancreatic duct interruption. Imaging findings showed a 25-mm-diameter mass lesion located in the pancreatic head. Endoscopic ultrasonography (EUS)-guided fine-needle aspiration (FNA) was performed on the mass. Cytology suggested adenocarcinoma, but the histological diagnosis was not confirmed. We made a comprehensive diagnosis of resectable pancreatic cancer. The mass shrank after preoperative adjuvant chemotherapy, and the patient underwent surgery. The final pathological diagnosis was type 2 autoimmune pancreatitis (AIP). Two years after surgery, AIP had not recurred in the remaining pancreas.