IgG4-associated cholangiopathy-mimicking Klatskin Tumor – Is surgery justfied in patients with normal IgG4 serum concentrations? A case report

IgG4-associated cholangiopathy is one manifestation of a recently recognized IgG4-associated disease entity characterized by elevated serum IgG4 levels, IgG4 lymphoplasmatic infiltration, and biliary duct strictures thus mimicking cholangiocarcinoma of the hilar bifurcation (Klatskin's tumor). The differentiation between benign strictures of the bile duct bifurcation and Klatskin's tumor is clinically challenging, but of critical importance because of the fundamentally different therapeutic approaches.

We report on a 72-year-old male patient presenting with significant jaundice and abdominal discomfort. Imaging examinations employing ERCP and MRCP scans consistently revealed a proximal bile duct stricture which is characteristic of Klatskin's tumor type IV according to the Bismuth classification. Since serum IgG4- levels were within the normal range, a benign Klatskin-mimicking lesion was unlikely. Thus the tumor board recommended operative therapy. The surgical procedure consisted of a hilar en bloc resection including an extended right hemihepatectomy and the resection of the extrahepatic bile ducts with lymphadenectomy. Reconstruction was performed by Roux-en-Y hepaticojejunostomy with the left hepatic duct. Subsequent to the operation there was a slight, temporary bile leakage from the resection surface. The patient's recovery was quick without signs of hepatic dysfunction. Unexpectedly, histology revealed an IgG4 associated cholangiopathy of the hilar bifurcation.

Seronegative IgG4 associated cholangiopathy-mimicking Klatskin's tumor is a rare condition. Given this presumed malignant situation, an extended surgical approach is justified and mandatory, even with the risk of over-treatment in the case of some benign lesions when detected postoperatively in the histology of the resected specimen.