Staging cholangiocarcinoma by cholangioscopy.

Peroral cholangioscopy (POCS) and percutaneous transhepatic cholangioscopy (PTCS) were first developed in the 1970s, and technical developments and clinical applications have taken place gradually ever since. POCS is used to diagnose small mucosal biliary lesions in non-icteric patients and early malignant changes in patients with persistent primary sclerosing cholangitis (PSC). Although PTCS is a more invasive diagnostic procedure than POCS, it has the advantage of precise diagnosis with mapping biopsy in defining the proximal and distal extension of superficially spreading cholangiocarcinoma (CCA) or mucin-producing CCA, which is predominantly found in papillary type CCA. POCS is significantly superior to ERCP in distinguishing between malignant and benign dominant bile duct stenoses in patients with PSC. The positive rate of PTCS biopsy for CCA is 96%, while morbidity and mortality of PTCS are 9% and 0%, respectively. Although magnetic resonance (MR) cholangiography may replace PTCS in determining the longitudinal spread of infiltrating type hilar CCA, the accuracy of MR cholangiography in papillary type hilar CCA is significantly lower than that of PTCS.