title: A Case of Autoimmune Cholangitis Misdiagnosed for Cholangiocarcinoma: How to Avoid Unnecessary Surgical Intervention?
abstract: BACKGROUND
  Autoimmune cholangitis or immunoglobulin G4-associated cholangitis (IAC) has been recently regarded as a new clinical and histopathological entity and is a part of a complex autoimmune disorder--IgG4-related systemic disease (ISD). ISD is an autoimmune disease with multi-organic involvement, characterized with IgG4-positive plasmocytic infiltration of various tissues and organs with a consequent sclerosis, which responds well to steroid therapy. Most commonly affected organs are the pancreas (autoimmune pancreatitis, [AIP]) and the common bile duct (IAC). IAC and cholangiocarcinoma (CCA) share many clinical, laboratory and imaging findings.
  
  
  METHODS
  We present a case of a 60-year-old male with a biliary stricture of a common bile duct, which was clinically considered as a bile duct carcinoma and treated surgically. Definite histopathological findings and immunohistochemistry revealed profound chronic inflammation, showing lymphoplasmacytic IgG-positive infiltration of a resected part of a common bile duct, highly suggestive for the diagnosis of IAC. In addition, postoperative IgG4 serum levels were also increased.
  
  
  CONCLUSIONS
  It is of primary clinical importance to make a difference between IAC and CCA, in order to avoid unnecessary surgical intervention. Therefore, IAC should be considered in differential diagnosis in similar cases.
authors.forename: Igor I
authors.initials: II
authors.lastname: Ignjatović
authors.forename: Slavko V
authors.initials: SV
authors.lastname: Matić
authors.forename: Vladimir D
authors.initials: VD
authors.lastname: Dugalić
authors.forename: Djordje M
authors.initials: DM
authors.lastname: Knežević
authors.forename: Marjan T
authors.initials: MT
authors.lastname: Micev
authors.lastname: Marko D Bogdanović
authors.forename: Srbislav M
authors.initials: SM
authors.lastname: Knežević
mesh_terms: D001327:Autoimmune Diseases / Q000175:diagnosis* / Q000276:immunology; D001650:Bile Duct Neoplasms / Q000175:diagnosis* / Q000601:surgery; D018281:Cholangiocarcinoma / Q000175:diagnosis* / Q000601:surgery; D002761:Cholangitis / Q000175:diagnosis* / Q000276:immunology; D003937:Diagnosis, Differential; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D019564:Unnecessary Procedures
chemical_list: D007074:Immunoglobulin G