A case of right hepatic duct entering cystic duct successfully treated by laparoscopic subtotal cholecystectomy through preoperatively placed biliary stent

Background Laparoscopic cholecystectomy is a well-established surgical procedure and is one of the most commonly performed gastroenterological surgeries. Therefore, strategy for the management of rare anomalous cystic ducts should be determined. Case presentation A 56-year-old woman was admitted to our hospital owing to upper abdominal pain and diagnosed with acute cholecystitis. Magnetic resonance cholangiopancreatography suspected that several small stones in gallbladder and the right hepatic duct drained into the cystic duct. Endoscopic retrograde cholangiopancreatography confirmed the cystic duct anomaly, and an endoscopic nasobiliary drainage catheter (ENBD) was placed at the right hepatic duct preoperatively. Intraoperative cholangiography with ENBD confirmed the place of division in the gallbladder, and laparoscopic subtotal cholecystectomy was safely performed. Conclusions The present case exhibited rare right hepatic duct anomaly draining into the cystic duct, which might have caused biliary tract disorientation and bile duct injury (BDI) intraoperatively. Any surgical technique without awareness of this anomaly preoperatively might insufficiently prevent BDI, and preoperative ENBD would facilitate safe and successful surgery.