Endoscopic approach to indeterminate biliary strictures.

Diagnosis of biliary strictures remains challenging because of the low sensitivity of conventional transpapillary sampling using endoscopic retrograde cholangiopancreatography. New devices and tips have been developed to increase the diagnostic yield of conventional transpapillary sampling. However, additional endoscopic procedures are often necessary for indeterminate biliary strictures. Two major approaches for indeterminate biliary strictures are endoscopic ultrasonography-guided sampling and peroral cholangioscopy (POCS)-guided biopsy. The selection of modalities should be considered based on the stricture location. Although endoscopic ultrasound is the preferred approach for distal biliary strictures, POCS is preferred for perihilar biliary strictures. Endoscopic ultrasonography-guided sampling is highly sensitive in cases with a mass, but the sensitivity of POCS-guided biopsies is unsatisfactory, and discrepancy with the visual diagnosis of POCS is common. Whether these advanced techniques should be performed as the initial procedure or as a rescue after a failed diagnosis by conventional transpapillary sampling needs to be clarified in terms of diagnostic yield and cost-effectiveness.