Diagnosis: Cholangiocarcinoma and Primary Sclerosing Cholangitis
• The major hepatobiliary malignancy for which patients with large duct primary sclerosing cholangitis (PSC) are at risk is cholangiocarcinoma. Cholangiocarcinoma develops in approximately 10% of patients with PSC, but the lifetime risk in patients with PSC is approximately 5% to 36%.
• Liver needle biopsies in PSC are problematic and low yield in detecting biliary dysplasia preceding PSC; the major perihilar bile ducts show a greater predilection for dysplastic lesions and should be sampled when evaluating explant specimens of PSC.
• Risk factors for cholangiocarcinoma in PSC include long history of inflammatory bowel disease, ulcerative colitis with colorectal neoplasia, dominant strictures, smoking, and ethanol consumption.
• Brush cytology of suspicious major strictures is diagnostically useful and is enhanced by the use of fluorescence in situ hybridization (FISH) with evaluation for the presence of polysomy (a four-probe set including chromosomes 3, 7, 17, and band 9p21), trisomy, or tetrasomy (as defined in specific publications).
• FISH results from brush cytology specimens need to be interpreted in light of other higher risk factors for cholangiocarcinoma, such as presence of dominant strictures, recent weight loss, abdominal pain, and elevated serum CA19-9.
