True left-sided gallbladder (medioposition): a rare intraoperative biliary tract variation during laparoscopic cholecystectomy

Abstract Purpose A left-sided gallbladder (LSGB) is a rare congenital biliary anomaly defined by the location of the gallbladder to the left of its usualanatomical position without situs inversus. True LSGB is further classified into medioposition and sinistroposition based on its relationto the ligamentum teres. With a reported prevalence of 0.04–0.3% among cholecystectomy patients, this anomaly is clinicallysignificant due to its frequent association with biliary and vascular variations that increase the risk of bile duct injury duringlaparoscopic cholecystectomy. This report highlights the intraoperative recognition and safe laparoscopic management of a trueLSGB (medioposition) and discusses its surgical implications. Case Presentation A 42-year-old obese female (BMI 36.5 kg/m²) presented with recurrent biliary colic. Preoperative ultrasonography revealed a solitarycalculus impacted at the gallbladder neck, with no reported anatomical abnormality. During laparoscopic cholecystectomy, thegallbladder was unexpectedly found on segment IVB, medial to its usual position and to the right of the ligamentum teres, consistentwith true LSGB (medioposition). Intraoperatively, the right hepatic artery was observed crossing anterior to the common bile duct.Additional technical challenges included an impacted Hartmann’s pouch stone and the presence of two cystic arteries. Carefuldissection with strict adherence to the critical view of safety allowed safe identification of biliary structures and successful completionof the procedure laparoscopically. The postoperative course was uneventful. Conclusion True LSGB is often undetected on routine preoperative imaging and presents as an intraoperative surprise. Surgeons must maintaina high index of suspicion when encountering atypical anatomy during cholecystectomy. Understanding the anatomical variationsassociated with LSGB and meticulous application of the critical view of safety are essential to prevent bile duct injury and ensure safesurgical outcomes.