Left-sided gallbladder associated with an accessory liver lobe and portal vein trifurcation encountered during laparoscopic cholecystectomy: a case report.

A 37-year-old man presented with epigastric pain, nausea, vomiting, and diarrhoea. Ultrasound demonstrated cholelithiasis with a stone impacted at the gallbladder neck. During laparoscopic cholecystectomy, the gallbladder was found to the left of the falciform ligament and was attached to an accessory liver lobe by a peritoneal fold containing vascular structures. Meticulous dissection and achievement of the critical view of safety allowed safe completion of the procedure without biliary or vascular injury. Postoperative magnetic resonance imaging with magnetic resonance cholangiopancreatography demonstrated a pedunculated accessory liver lobe arising from segment IV and a trifurcation-type portal vein anomaly without biliary obstruction. This case illustrates how coexisting congenital hepatobiliary and vascular variants can alter intraoperative orientation and highlights the importance of anatomy-based dissection when unexpected anatomy is encountered during laparoscopic cholecystectomy.