Case report: A female case of isolated IgG4-related sclerosing cholangitis mimicking cholangiocarcinoma

RATIONALE: IgG4-related disease is a newly recognized fibroinflammatory disorder, characterized by tumefactive lesions, storiform fibrosis and IgG4-positive plasma cells infiltration. IgG4-related sclerosing cholangitis (IgG4-SC) is the most common extrapancreatic manifestation of IgG4-related disease, but it is frequently associated with autoimmune pancreatitis(AIP). Only few case was reported to be diagnosed with IgG4-SC in the absence of AIP, with a striking male preponderance. Here we report a female case of isolated IgG4 related sclerosing cholangitis mimicking cholangiocarcinoma. PATIENT CONCERNS: A 58-year-old woman complaint of one-month history of jaundice and right upper quadrant discomfort, and the biliary reconstruction showed full-length wall thickening and segmental stenosis. DIAGNOSES: Cholangiocarcinoma was then diagnosed. INTERVENTIONS: Choledochoplasty was performed, followed by Roux-en-Y anastomosis. OUTCOMES: However, pathological examination revealed IgG4-related sclerosing cholangitis (IgG4-SC) and the retrospective measurement of serum IgG4 was 346 mg/dL post-operatively. The patient was followed for another nine monthswithout recurrence. LESSONS: The differential diagnosis between cholangiocarcinoma and IgG4-SC is challenging due to significant overlap of clinical manifestations, lab tests and imaging characteristics. However, as an afterthought of this case, typical cholangiocarcinoma rarely presents full-length wall thickening. What the case taught us was pre-operative IgG4 measurement for patients with long bile duct involvement was highly recommended in order to rule out IgG4-SC.