Choledochal cyst type I with dilated intrahepatic biliary radicles: a type IVA mimic

Background A choledochal cyst is a relatively rare congenital anomaly of the biliary tree requiring surgery as the definitive treatment. Amongst the five Todani variants, type I poses a diagnostic and treatment challenge owing to its infrequent, yet clinically significant mimicry for type IVA cysts. Case presentation We present a case of a 4-year-old female diagnosed to have a giant type IA choledochal cyst that mimicked a type IVA cyst on radiological imaging. The patient was treated by complete cyst excision, cholecystectomy, and restoration of the biliary-enteric communication by a Roux-en-Y hepaticojejunostomy. Regression of the dilated intrahepatic radicles that counterfeited a type IVA cyst was confirmed on follow-up imaging studies. Conclusion Such an encounter, although rare, can significantly alter the course of management. We recommend extrahepatic cyst excision with biliary reconstruction as the standard treatment when preoperative and intraoperative imaging studies fall short in differentiating the aforementioned variants.