In which of the following conditions " Onion Skin" fibrosis of bileduct is seen: (A) Ulcerative collitis, (B) Primary sclerosing cholangitis, (C) Primary biliary cirrhosis, (D) Cholangiocarcinoma
Answer is B. Concentric periductal fibrosis is known as onion skin fibrosis and is classical of Primary sclerosing cholangitis.