Usefulness of laparoscopy and intraductal ultrasonography in a patient with isolated immunoglobulin G4-related sclerosing cholangitis

Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is often associated with type 1 autoimmune pancreatitis, and the frequency of isolated IgG4-SC seems to be quite low, making the diagnosis of isolated IgG4-SC challenging. A 63-year-old male was admitted to our hospital for frequent fever. Abdominal magnetic resonance cholangiopancreatography showed diffuse narrowing of the common bile duct and post-stenotic dilatation of the right posterior bile duct. Laboratory tests showed abnormalities in the levels of hepatobiliary enzymes and serum IgG4 levels. Endoscopic retrograde cholangiopancreatography showed diffuse narrowing of intrahepatic bile ducts and post-stenotic dilatation of the right posterior bile duct but no abnormalities in the pancreas. Intraductal ultrasonography showed symmetric circumferentially thickened walls of both narrowed and non-narrowed common bile ducts. Histologic examination of the common bile duct mucosa showed infiltration of IgG4-positive plasma cells. Laparoscopic observations showed discoloration with red lobular markings and multiple small depressed lesions. Liver histology showed mild cholangitis with infiltration of IgG4-positive plasma cells around the bile ducts. From these findings, the patient was diagnosed with isolated IgG4-SC. After treatment with a steroid, bile duct dilatations improved. Laparoscopy and intraductal ultrasonography were useful to diagnose isolated IgG4-SC.