Left-sided gallbladder on the basis of a right-sided round ligament.

Left-sided gallbladder, a rare congenital anomaly, is defined as a gallbladder located to the left of the round ligament. A 42 year-old female underwent a cholecystectomy for gallstone disease. At laparotomy, we found that the round ligament was located to the right of its normal position and was continuous with the right anterior branch of the portal vein. Though normally situated, the gallbladder was therefore, on the left side of the anomalously right-sided round ligament, fulfilling the definition of a left-sided gallbladder. This case indicates that a third type of left-sided gallbladder may occur in addition to the other forms: one resulting from a right-sided round ligament, in addition to the "true" left-sided gallbladder and the variety seen in situs inversus.