Table 1.

Phenotypic Variants of PSC

Varianta	Cholangiographic Features	Liver Histology Features
Classic PSC	Multifocal intrahepatic and extrahepatic strictures and resultant upstream (ie, proximal) ductal dilation	Typical changes (ie, nonsuppurative paucicellular cholangitis, periductal fibrosis, ductular reaction, and ductopenia)
Intrahepatic PSC	Multifocal intrahepatic strictures and resultant upstream (ie, proximal) segmental ductal dilation	Typical changes
Extrahepatic PSC	Extrahepatic-only strictures and resultant upstream (ie, proximal) ductal dilation	Nondiagnostic or nonspecific features of cholestasis, particularly in early-stage disease
Small-duct PSC	Normal findings	Typical changes

^aAll of these variants will generally have a cholestatic serum biochemical profile, although a small minority of patients can have normal serum liver test results.

PSC, primary sclerosing cholangitis.