Autoimmune pancreatitis with pancreatic calculi and pseudocyst: a case report.

Autoimmune pancreatitis (AIP) is a unique form of pancreatitis often associated with infiltration of immunoglobulin G4-positive cells, a swollen pancreas, and diffuse narrowing of the pancreatic ducts. Unlike acute pancreatitis, AIP is rarely complicated with pseudocysts. Pancreatic calculi, a feature of ordinary chronic pancreatitis, are unusual during short-term follow-up in patients with AIP. We herein describe a 46-year-old man who initially presented with a submucosal tumor of the stomach. The patient was finally diagnosed with AIP accompanied by a pancreatic tail pseudocyst located in the gastric wall and pancreatic calculi by endoscopic ultrasonography-guided fine-needle aspiration. He underwent endoscopic retrograde cholangiopancreatography, pancreatic duct stent placement, and steroid treatment and achieved good clinical and laboratory responses. Although AIP is a common autoimmune disease that responds well to steroids, pseudocysts and pancreatic calculi are rare manifestations of AIP and should be given special attention, especially in patients with disease relapse.