Table 4.

Staging of PSC

Stage	Features
I	Enlargement, edema, and scarring of the portal triads, and mononuclear cell infiltration with some piecemeal necrosis and damage to isolated bile ducts. Proliferation of interlobular bile ducts with mononuclear and polymorphonuclear cells may also be present, although the inflammation is usually less dense than in primary biliary cholangitis
II	Expansion of portal triads with fibrosis extending into the surrounding parenchyma
III	Bridging fibrosis
IV	Cirrhosis

Abbreviation: PSC, primary sclerosing cholangitis.