Biliary dysplasia as a marker of cholangiocarcinoma in primary sclerosing cholangitis

Background/Aims: Indentification of biliary dysplasia in a primary sclerosing cholangitis (PSC) liver biopsy may indicate developing cholangiocarcinoma. The objectives were to determine whether biliary dysplasia can be recognised reproducibly in PSC and to compare the frequency in cases with and without cholangiocarcinoma. Methods: Liver biopsies from 26 PSC cases with concurrent or subsequent cholangiocarcinoma (within 2 years) were assessed for biliary dysplasia independently by three liver pathologists. This was done in two stages: initially, without agreement on criteria, and subsequently after such agreement. Liver biopsies from 60 PSC cases without cholangiocarcinoma were also assessed. Results: Reproducibility for biliary dysplasia without prior agreement on criteria was only marginally better than random (kappa=0.129). In contrast, after prior agreement on criteria, reproducibility was moderate (kappa=0.44). Biliary dysplasia was agreed to be present by all three pathologists in 23% and 19% of biopsies in the first and second round, respectively, from patients with cholangiocarcinoma, but in none of the patients without cholangiocarcinoma. Conclusion: Criteria for biliary dysplasia can be agreed and the entity recognised in liver biopsies. The strong association of biliary dysplasia with cholangiocarcinoma in PSC suggests use of dysplasia as a marker for current or developing malignancy.