Isolated cystic duct cyst in a child ：A case report

Abstract Background: Dilatation of the common bile duct is a common biliary malformation in children. However, isolated cysts of the cystic duct are extremely rare and not included in the Todani classification; this case report presents an exceptional case of an 8-year-old male child with an isolated cystic duct cyst. Case presentation An 8-year-old male presented to the local hospital with intermittent abdominal pain. Abdominal ultrasonography (USG) conducted at the local hospital revealed dilatation of the upper segment of the common bile duct, while Abdominal CT indicated dilatation of the upper segment of the common hepatic duct. The patient was admitted to our hospital, and all laboratory results were within normal limits. CT reveals slightly dilated intrahepatic bile ducts, tortuous dilatation of the cystic ducts, and a common bile duct diameter of approximately 2.0 mm.MRCP indicates dilatation of the cystic ducts associated with multiple stones, Todani type II choledochal cysts, , and the possibility of PBM cannot be excluded.Endoscopic retrograde ERCP was conducted: acyst was observed in the superior segment of the cystic duct, several calculi were identified within the cyst, and a duct was noted leading to the gallbladder at the cyst's tail, with a common duct of around 10 mm, classified as a cystic duct cyst. The youngster underwent Da Vinci robot-assisted biliary tract exploration, which verified the dilation of the cystic duct, resection of the gallbladder and cystic duct, and the insertion of a T-tube for external drainage in the remains of the cystic duct. Thepathology results indicated the presence of gallbladder tissue. The patient's postoperative recuperation was uneventful. T-tube imaging was conducted in two mouths post-operation, revealing no dilation of the common bile duct.The T-tube was removed, and USG of the intra- and extra-hepatic bile ducts was conducted in three mouths post-operation, revealing no abnormalities or dilation of the common bile duct. Conclusion: Choledochal cyst is an uncommon biliary tract anomaly characterized by vague clinical presentations and laboratory findings.MRCP imaging possesses diagnostic significance; ERCP can elucidate the diagnosis through sequential imaging, while surgical dilation of the choledochal duct serves as the conclusive basis for diagnosis.Aconsensus has been established regarding the concurrent resection of the gallbladder and choledochal duct cysts. For pediatric patients presenting with a combination of choledocholithiasis, common bile duct dilation, and PBM, atailored surgical plan may be devised according to the child's specific circumstances. For pediatric patients with biliary tract anomalies, including bile duct calculi, dilated common bile duct, andPBM, the surgical strategy can be tailored to the child's specific circumstances.