Isolated cystic duct cyst with associated stones in a 4-month-old boy

Isolated cystic duct cysts are rare entities, with few cases having been reported. We present the case of a 4-month-old male patient presenting with abdominal pain and vomiting. Ultrasonography and magnetic resonance cholangiopancreatography revealed an isolated cystic duct cyst with associated stones. The patient underwent open cholecystectomy with complete cyst excision and cystic duct transection; there were no postoperative complications. While lesions like the one described herein are extremely rare, they should be included as a separate category in classifications of choledochal cysts.