Biliary duplication cyst with heterotopic gastric mucosa resulting in obstruction of the biliary system: a case report.

Biliary tract duplication cysts with heterotopic gastric mucosa are rare congenital anomalies, with our case representing only the fourth reported case in the literature. An 8-year-old girl with several months of abdominal pain was found to have a complex cystic mass communicating with the biliary system via the common hepatic duct. Intraoperatively, inflammation caused by the cystic mass was found to have resulted in a Mirizzi-like syndrome, with a nearly complete obstruction at the confluence of the left and right hepatic ducts. Histopathologic examination of the biliary mass revealed it to be a duplication cyst lined by heterotopic gastric mucosa with secondary ulceration and fibrosis. Biliary duplication cysts are a rare but important process that should be considered in a child with a mass in the portal triad and biliary obstruction.