1426 Type 1 Choledochal Cyst With Anomalous Pancreaticobiliary Malunion Diagnosed on Cholangioscopy

Abstract

INTRODUCTION: Choledochal cysts are cystic dilatations found within the intra and/or extrahepatic bile ducts. Untreated choledochal cysts can lead to increased risk for strictures, pancreatitis, cholangitis, gallbladder cancer, cholangiocarcinoma and pancreatic cancer. Early and accurate identification of choledochal cysts is crucial to determine appropriate medical and surgical planning. We present a case of a patient with a type 1 choledochal cyst with anomalous pancreaticobiliary malunion. CASE DESCRIPTION/METHODS: A 42-year-old female with a PMH of a cholecystectomy and known biliary cyst presented with acute onset abdominal pain. MRCP demonstrated a 5.5 cm fusiform dilatation of the common bile duct (CBD). EUS confirmed a CBD dilatation (Figure 1). ERCP with spyglass cholangioscopy showed an abnormal pancreaticobiliary junction with a common channel about 1 cm long leading to two separate openings, one to the CBD/choledochal cyst and another to the pancreatic duct orifice (Figure 2). Fluoroscopy showed contrast filling a dilated cystic structure in the proximal CBD consistent with a choledochal cyst (Figure 3). A 7 French × 7 cm flex stent was deployed into the CBD. Findings were consistent with a type 1 choledochal cyst and an anomalous pancreaticobiliary malunion. Patient underwent ex-lap with resection of the choledochal cyst with roux-en-y hepaticojejunostomy creation, which she tolerated well. DISCUSSION: The Todani classification is based on cyst location and bile duct dilatation. There are 5 types with type 1 as the most common which comprises of 80-90% of all choledochal cysts. Type 1 choledochal cysts involve fusiform dilatation of the entire CBD without any intrahepatic dilatation. Cancer is more common in patients who are older and with type I and IV cysts. These are typically treated with complete cyst resection and Roux-en-Y hepaticojejunostomy. Additionally, 50-80% of patients with choledochal cysts have an anomalous pancreaticobiliary malunion. The KOMI classification is used to classify anomalous pancreaticobiliary malunions into 3 types, which is based on the CBD/pancreatic duct angle and presence of CBD dilation. This case was a KOMI type IIB anomalous pancreaticobiliary malunion given the common hepatic and pancreatic ducts join each other at an acute angle creating a single common channel.