Ectopic gallbladder with congenital biliary dilatation: a pediatric case report

BACKGROUND: An ectopic gallbladder is a rare anomaly and can result in the misinterpretation of imaging findings and clinical confusion. Knowledge of such anomalies facilitates accurate diagnoses and prompt management. We report a pediatric case of an ectopic gallbladder concomitant with congenital biliary dilatation (CBD). CASE PRESENTATION: A 9-year-old girl was referred to our hospital for elevated liver enzyme levels. Following physical examination and a review of medical imaging findings, she was diagnosed with Todani type IV-A CBD. We could not visualize the gallbladder by abdominal ultrasonography, CT, and MRI scans; therefore, we suspected gallbladder agenesis. A laparoscopic excision of the extrahepatic bile duct was performed to treat the CBD. Neither a gallbladder nor a cystic duct were revealed on the liver undersurface. Therefore, gallbladder agenesis was considered as a diagnosis based on preoperative imaging and intraoperative findings. However, during dissection of the hepatic hilum, a cyst-like structure was found on the ventral side of the common hepatic duct, slightly to the right, and a small additional duct that originated from the cystic structure was found. Upon incision, a small amount of bile was drained from the small duct. Thus, the cystic structure was diagnosed as an ectopic gallbladder with hypoplasia. Following the removal of the ectopic gallbladder, the extrahepatic bile duct was excised. Subsequently, laparoscopic Roux-en-Y hepaticojejunostomy was performed without any complications. Postoperative histopathological evaluations of the resected specimen revealed Rokitansky–Aschoff sinuses in the resected cystic lesion. The pathological investigations confirmed the diagnosis of an ectopic gallbladder. Following an uneventful postoperative course, the patient was discharged on day nine. CONCLUSIONS: To our knowledge, this is the first pediatric case report describing an ectopic gallbladder concomitant with CBD. If the gallbladder cannot be detected in a preoperative imaging examination, it is important to consider the possibility of an ectopic gallbladder.