Long-standing indeterminate biliary stricture with iterative negative tissue sampling revealed as cholangiocarcinoma under SpyGlassTM cholangiocoscopy.

Bile duct brush cytology, intraductal biopsy and EUS-FNA are all used to characterize biliary strictures, with suboptimal sensitivity. Surgical resection without confirmed malignancy is undesirable. Cholangioscopy with targeted biopsies appears to increase the diagnostic yield in indeterminate biliary strictures, but it is still considered optional.