Biliary stenosis not associated with a mass is difficult to diagnose with certainty. The diagnosis is usually based on a first-line cytological study of biliary brushing, which allows a diagnosis in 30 to 50% of cases. In the event of negativity, it is then possible to perform a cholangioscopy in a second step, which allows better sensitivity by performing biopsies. Performing cholangioscopy from the start could potentially save time and avoid disturbances associated with intermediate biliary stenting.

The main objective is to compare two strategies for exploring indeterminate biliary stenosis (1st vs. 2nd line retrograde cholangioscopy) in terms of diagnostic performance. The secondary objectives are to compare the same two strategies in terms of effectiveness, side effects and cost-effectiveness.

The primary outcome measure is the diagnostic yield (performance) of the initial investigation of indeterminate biliary stenosis: cytological brushing followed by cholangioscopy in case of failure (control group) or cholangioscopy from the start (study group).

Inclusion Criteria:

• Presence of intra- or extrahepatic biliary stenosis, involving the main bile ducts: common hepatic duct, right and left hepatic ducts
• Presence of clinical jaundice and / or biological cholestasis (GGT> 3N)
• Absence of visible mass near the biliary stenosis after initial morphological assessment by abdominal CT scan, MRI with biliary sequences.
• Endoscopic ultrasound performed and not having allowed the acquisition of material of diagnostic interest by guided puncture of the lesion.
• No history of ERCP in the 6 months preceding inclusion and no biliary prosthesis (plastic or metal) in place at the time of inclusion
• Collegial validation of the need for a formal diagnosis of indeterminate biliary stenosis in order to guide therapeutic management
• Patients aged 18 to 85
• Patient who gave his consent to participate in the study
• No contraindication to anesthesia (ASA 1, 2,3)
• Patient affiliated to a social security scheme (beneficiary or beneficiary)
• Absence of pregnancy and current contraception in women of childbearing age

Exclusion Criteria:

• Presence of a manifest tissue mass in relation to the biliary stenosis on CT and / or MRI imaging.
• Very strong presumption of the etiological diagnosis of biliary stenosis given the history (history, background): i.e. liver surgery, cholecystectomy, autoimmunity
• History of ERCP and / or percutaneous biliary drainage in the 6 months preceding inclusion
• Presence of a plastic or metal biliary prosthesis in place at the time of inclusion
• History of cephalic duodeno-pancreatectomy or hepatico-jejunal anastomosis
• Non-passable stenosis of the main bile duct
• Severe coagulopathy, thrombocytopenia <75,000 G / L, treatment with clopidogrel cannot be interrupted even temporarily
• Anesthetic contraindication (ASA 4)
• Inability to obtain informed consent
• person deprived of liberty