Neuroendocrine tumor of the common hepatic duct, mimicking a choledochal cyst in a 6-year-old child.

We report a rare case of a neuroendocrine tumor of the extrahepatic biliary tree in a child. A 6-year-old girl who presented with jaundice and pruritus was found to have elevated liver enzymes along with a cystic dilatation of the common hepatic duct. After further diagnostic testing, a working diagnosis of a type I choledochal cyst was established. Laparotomy revealed hydrops of the gall bladder, an elongated and dilated cystic duct and a cystic dilatation of the common hepatic duct. An unusually thickened common bile duct was also noted at the time. Follow-up histology revealed an invasive neuroendocrine tumor which lead to a second look operation in which extended resection and lymphadenectomy was performed. No histological or gross pathological evidence of lymph node metastasis was found. Postoperatively the patient continues doing well 2 years after the original diagnosis was established. Neuroendocrine tumors of the extrahepatic bile duct are extremely rare with only 4 pediatric cases of a total of 51 cases published in the literature. To our knowledge, this is the youngest patient reported so far. The rarity of this entity made it challenging to diagnose a case of a neuroendocrine tumor in an atypical location that radiologically mimicked a choledochal cyst.