 - Clinical diagnosis of PSC as evident by chronic cholestasis of more than six months duration with either a consistent magnetic resonance cholangiopancreatography MRCPendoscopic retrograde cholangiopancreatography ERCP showing sclerosing cholangitis, or a liver biopsy taken at any time consistent with PSC in the absence of a documented alternative etiology for sclerosing cholangitis. If diagnosis of PSC was made by histology alone, it must require the presence of fibro-obliterative lesions ie, onion skin lesions 