Choledochal cysts (CC) is a rare congenital anomalies of biliary tract, characterized by dilatation of biliary duct. CC is commonly seen in Asian population and primarily seen in children. Early resecttion of choledochal cyst will reduce the risk of cholangiocarcinoma. We report a 11-year-old Javanese girl, already diagnosed with choledochal cyst todani classification type IVa from US examination and MRCP examination since she was 7 years old. She had history of jaundice since birth. She had drainage procedure, but the cyst was unresected. Patient failed to show up routine follow up, and came back to Hospital when she was 11 years old due to blood production from external drainage. MRCP examination result was solid mass malignant characteristic on common hepatic duct until distal common bile duct suspected cholangiocarcinoma. The association between choledochal cyst and cholangiocarcinoma is well established and when undetected or treated inappropriately, tumour can arise from both cysts and undilated parts of the biliary tree. Type IV choledochal cysts, have the highest risk of malignancy. Cholangiocarcinoma is most frequently seen in type I and IV CC, despite extremely rare in the pediatric population. Follow up with imaging modality such as ultrasound (US) abdominal examination and MRCP examination will allow early detection in any complication that may occur in choledocal cyst cases.