Abstract
A 90-year-old woman presented with swelling of the pancreas on plain computed tomography (CT). Contrast-enhanced CT and magnetic resonance imaging (MRI) revealed an irregularly-attenuated mass at the ventral side of the pancreatic head-to-body transition. Swelling of the body and tail of the gland was also noted with a "sausage-like appearance" and homogenous delayed enhancement, skipped narrowing of the main pancreatic duct with "icicle sign", and diffuse swelling of the branch ducts. The serum IgG4 level was 757mg/dl. Upper gastrointestinal endoscopy revealed swelling of the duodenal papilla and multiple fish-egg-like protrusions at the fistula orifice filled with mucin in the duodenal bulb formed by the pancreatic tumor. Biopsy specimens from the papilla showed abundant IgG4-positive plasma cell infiltration, and tissues from the fistula orifice revealed papillary growth of high-grade atypical columnar epitheliums suggesting intraductal papillary mucinous neoplasm (IPMN) with high-grade dysplasia and highly-atypical tubular glands scattered in the stroma with marked infiltration of IgG4-positive cells. Accordingly, a diagnosis of intraductal papillary-mucinous carcinoma (IPMC) invasion was made, and coexisting autoimmune pancreatitis (AIP) was strongly suspected. To our knowledge, invasive IPMC with AIP has not been reported. We report this case and discuss the relationships between AIP and pancreatic cancer or IPMN.
