Isolated Liver Hilar Infiltration by IgG4 Inflammation Mimicking Cholangiocarcinoma.

IgG4-related disease represents a heterogeneous group of disease characterized by infiltration of various tissues by IgG4 plasmocytes. In case of liver infiltration, this condition classically mimics primary sclerosing cholangitis or multifocal cholangiocarcinoma due to inflammation that preferentially affects the intra- and extrahepatic bile duct. Diagnostic criteria have recently been reviewed in order to better define the disease and help physicians make the diagnosis. Herein, we present the case of a patient who died after liver surgery for suspected cholangiocarcinoma that finally turned out to be IgG4-associated liver disease, a condition being out of current consensual criteria. The patient presented with progressive cholestasis identified by MR cholangiography as an isolated hilar mass responsible for dilatation of the left and right intrahepatic bile duct suspicious for a Klatskin tumor. The IgG4 blood level was normal as was biliary cytology. The patient underwent right portal embolization followed by right extended hepatectomy. Pathologic examination found no tumor but intense fibrosclerotic infiltration with a marked inflammatory infiltrate characterized by IgG4-positive plasmocytes. Despite immunosuppressive treatment, cholestasis was never controlled and successive biopsies of the remaining liver showed progressive cholestasis, liver infiltrate and no bile duct regeneration. The patient finally presented an upper gastrointestinal hemorrhage leading to death 4 months after hepatectomy and appropriate immunosuppressive therapy.