Aberrant biliary anatomy: endoscopist's nightmare.

A 55-year-old woman with a diagnosis of metastatic gallbladder adenocarcinoma underwent ERCP for palliation of distal biliary obstruction by a malignant lymph nodal mass. On ERCP, only part of the right ductal system along with the gallbladder (GB) was opacified with contrast material (A), and multiple attempts to fill the remaining biliary system failed. An 8-cm uncovered biliary self-expandable metal stent (SEMS) was placed. However, after stent placement, the patient’s jaundice increased, and imaging revealed persistence of dilation of the biliary system. CT revealed persistence of the biliary dilation, and the SEMS was observed posterior to the dilated common bile duct (CBD) (B). Percutaneous transhepatic biliary drainage (PTBD) was done via the left hepatic duct (LHD). Contrast material injected through the PTBD catheter opacified the left and right posterior ductal system (C). The biliary system containing the previously placed SEMS, and the right anterior system, were not opacified, which suggested aberrant biliary anatomy in the form of a combined Huang type A3 intrahepatic biliary system and Choi type Va double common bile duct (D), with SEMS placed via ERCP in the CBD, draining the right anterior system (RASD) via the right hepatic duct (RHD), along with the cystic duct (CD), and the SEMS placed via PTBD in the CBD draining the left and right posterior system (RPSD). A review of the CT of the abdomen obtained before ERCP by doing a coronal reconstruction suggested the possibility of a double CBD (D). The patient’s serum bilirubin normalized after PTBD, and she was referred to the oncology services for palliative chemotherapy.