(A) Macroscopic examination shows a whitish nodular mass spreading along the hilar bile duct to B3. Arrowheads show the hepatic IPT and arrow shows the bile duct wall. (B) Histological appearance, with diffuse and severe lymphoplasmacytic infiltration (Hematoxylin & Eosin). Arrowheads show the hepatic inflammatory pseudotumor and arrow shows the bile duct wall. (C) Immunohistochemistry demonstrates abundant plasma cells positively stained by anti-IgG4 antibody.