[A case requiring differentiation of IgG4-related sclerosing disease from periampullary cancer].

A 56-year-old man was admitted to our hospital with right upper quadrant abdominal pain. Laboratory investigations revealed liver dysfunction and elevation of serum HbA1C and CA19-9 levels. Computed tomography and magnetic resonance imaging revealed a diffuse enlarged pancreas, stenosis of the main pancreatic duct and lower bile duct, and retroperitoneal fibrosis. Endoscopic retrograde cholangiography showed stenosis of the lower bile duct. Endoscopic retrograde pancreatography demonstrated short-segmental, irregular narrowing of the main pancreatic duct. Brush cytology of biliary stenosis and biliary cytology were negative. The serum IgG and IgG4 levels were elevated. The observations were compatible with lgG4-related sclerosing diseases. Steroid hormone therapy (prednisolone) at a primary dose of 30 mg/day resulted in dramatic improvement of symptoms and of blood chemistry data in addition to shrinkage of the diffuse enlarged pancreas, and decreased the thickness of the bile ducts. Because malignant tumors are frequently suspected on initial presentation, IgG4-related sclerosing disease should be considered during differential diagnosis to avoid unnecessary surgery. We report this case of IgG4-related sclerosing disease that required differentiation from periampullary cancer.