[Cytology is in pivotal role at screening and surveillance of PSC].

Primary sclerosing cholangitis (PSC) is an autoimmune disease leading to biliary strictures and inflammation. The lifetime risk for cholangiocarcinoma (CCA) among PSC patients is 7-13%, and biliary dysplasia is thought to be a precursor lesion for CCA. The diagnosis of PSC is based on endoscopic retrogradic cholangiography (ERC). During ERC brush cytology samples are routinely taken in our unit to detect possible biliary dysplasia. With repeated cytological dysplasia, liver transplantation is considered. Aneuploidy in DNA flow cytometry may support the suspicion of dysplasia. PSC is the most common indication for liver transplantation in Finland, and half of transplantations are prophylactic.