Sinistroposition: A case report of true left-sided gallbladder in a Vietnamese patient

INTRODUCTION: Left-sided gallbladder without situs viscerum inversus (LSG-woSVI) is defined as a gallbladder located under the left lobe of the liver; to the left of the round/falciform ligament, but with all other viscera maintaining normal anatomical relationships. This is a rare congenital anomaly with a reported prevalence that ranges from 0.04% to 1.1%. It is usually an incidental intraoperative finding, and can be associated with anatomic abnormalities of the biliary tree, portal system and vasculature. LSG and associated variations may present significant challenges even for experienced surgeon. PRESENTATION OF CASE: LSG-woSVI was unexpectedly discovered in a 49-year-old, Vietnamese female during laparoscopic cholecystectomy. There were no pre-operative indications of sinistroposition. The cystic duct joined the common hepatic duct on the right side, and the cystic artery crossed anterior to the common bile duct in a right-to-left direction. Antegrade cholecystectomy was performed without intraoperative or postoperative complications. DISCUSSION: LSG is a rare anatomical variation that often remains undetected with ultrasound and pre-operative tests. Several hypotheses suggest underlying embryologic mechanisms for LSG and associated anomalies in ductal, portal and vascular anatomy, but the exact cause remains a mystery. Safe laparoscopic cholecystectomy can be done; however, there is an increased risk of injury to the major biliary structures compared to orthotopic gallbladder. CONCLUSION: Laparoscopic antegrade cholecystectomy is feasible for LSG. However, surgeons need to be cognizant of anatomy, so that rapid modifications of surgical technique can ensure positive patient outcomes.