Steroid Responsive Pancreatic Mass-Forming Type 2 Autoimmune Pancreatitis

Autoimmune pancreatitis (AIP) has two distinct subsets. Type 1 AIP or lymphoplasmacytic sclerosing pancreatitis is systemic disease with the elevation in serum levels of the IgG4. Type 2 AIP, also called duct-centric pancreatitis, features granulocyte epithelial lesions with duct obstruction in the pancreas without systemic involvement. Here, we report a case of type 2 AIP diagnosed by pathology, which is the first report in Korea. The case is a 56-year-old woman who presented with anorexia and vomiting. Computed tomography revealed mass-like lesion in the pancreatic head and the compression of the distal common bile duct and the head portion of the main pancreatic duct. Serum levels of the IgG4 were normal. Histologic examination revealed a dense neutrophil infiltration in the pancreatic parenchyme associated with extensive fibrosis, thereby confirming the diagnosis of type 2 AIP. The abnormalities in the clinical, laboratory, and radiological findings improved after oral steroid treatment.