title: The importance of IgG4 screening in patients diagnosed with primary sclerosing cholangitis in the past: A case rediagnosed as IgG4-SC after 10 years.
abstract: BACKGROUND
  While primary sclerosing cholangitis (PSC) has been recognized for decades, immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) has been correctly diagnosed only in recent years. PSC and IgG4-SC show similar clinical symptoms, serologic markers, and imaging results, but the treatment strategies and prognosis of patients differ.
  
  
  METHODS
  Here, we present the case report of a patient diagnosed with PSC for 10 years and rediagnosed with IgG4-SC recently, to emphasize the importance of screening serum IgG4 levels in patients with previous diagnosis of PSC.
  
  
  METHODS
  A 57-year-old woman with 10-year history of PSC was hospitalized due to pruritus. In 2004, the patient underwent cholecystectomy and cholangioenterostomy because of unexplained jaundice with pancreatic swelling. In the last 10 years, her liver enzyme levels were continuously elevated. The latest liver function profile showed elevated alanine aminotransferase, aspartate aminotransferase, and total bilirubin. IgG4 was 3.69 (0.03-2.01 g/L). Immunohistochemical staining of the surgical specimen showed >10 IgG4-positive plasma cells per high-power field, and IgG4+/IgG+ plasma cells >40%.
  
  
  RESULTS
  She was treated with prednisone 40 mg once-daily and the dose was gradually tapered. The patient remains well after 18 months.
  Patients with IgG4-SC may be misdiagnosed as PSC due to lack of IgG4 screening. It is important to perform IgG4 screening in patients diagnosed as PSC. Steroid is effective to prevent disease progression in these patients.
authors.affiliation: Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin Medical University Department of Radiology, Tianjin Medical University General Hospital, Tianjin Medical University Department of Pathology, Tianjin Medical University General Hospital, Tianjin Medical University Department of Postgraduate, International School of Tianjin Medical University, Tianjin, China.
authors.forename: Yanni
authors.initials: Y
authors.lastname: Li
authors.forename: Lu
authors.initials: L
authors.lastname: Zhou
authors.forename: Xin
authors.initials: X
authors.lastname: Zhao
authors.forename: Wenjing
authors.initials: W
authors.lastname: Song
authors.forename: Nathasha
authors.initials: N
authors.lastname: Karunaratna
authors.forename: Bangmao
authors.initials: B
authors.lastname: Wang
mesh_terms: D001652:Bile Ducts / Q000473:pathology; D015209:Cholangitis, Sclerosing / Q000097:blood / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D008875:Middle Aged
chemical_list: D007074:Immunoglobulin G