| The indeterminate biliary stricture is considered when a suspected malignant stricture has a negative or an inconclusive tissue acquisition under fluoroscopic guidance including brush cytology and fluoroscopic guided biopsy. The approach is mainly depended on the previous history of surgery or the endemic area of certain entities such as tuberculosis, inflammatory bowel disease, and IgG4 related cholangiopathy, etc. In those who presented with mass either suspected pancreatic tumor or lymph node metastasis, EUS with tissue acquisition may be the appropriate approach. Recently, cholangioscope has become an important tool to diagnose the indeterminate biliary stricture. Various cholangioscopes are available including baby-mother cholangioscope, single-operator per-oral cholangioscope, and direct per-oral cholangioscope. These could be classified as two types; the fiberoptic-based and video/digital-based cholangioscopes. The latter cholangioscope provides better image quality and overall diagnostic performance especially for cholangioscopy-guided biopsy than those of fiber-optic systems. Both direct visualization and targeted biopsy by cholangioscope play an important role to confirm malignant etiology (Figure one). |
