Filling Defect on ERCP: Biliary Cystadenoma, a Rare Tumor

Biliary cystadenomas are rare tumors of the bile ducts most commonly presenting as large right liver lobe lesions. These are usually slow-growing and mostly benign. They commonly present with abdominal pain. On physical exam an abdominal mass can be identified occasionally. Walls of biliary cystadenomas appear thicker than simple cysts, with soft tissue nodules and enhancing septations on CT or MRI. Radiographic images can vary with the amount of protein content in the fluid on CT or MRI. Due to the risk of malignant transformation, complete surgical resection is advised. Hereby, we describe a 37-year-old lady who presented to the outpatient clinic with bloating and abdominal discomfort with intermittent elevated liver enzymes and hyperbilirubinemia. Ultrasound of the liver and bile ducts followed by CT scan and magnetic resonance cholangiopancreatography confirmed the presence of biliary cystadenoma of the intra- and extrahepatic ducts. It was seen as a filling defect of the intra- and extrahepatic ducts (common hepatic duct) on endoscopic retrograde cholangiopancreatography. Involvement of the intra- and extrahepatic bile ducts simultaneously is a rare presentation of this tumor. She later on underwent exploratory laparotomy with extrahepatic bile duct resection, left hepatic lobe resection and reconstruction with hepaticojejunostomy. Pathology confirmed the presence of biliary cystadenoma with ovarian-like stroma. She had recovered uneventfully from the surgery when seen 2 weeks later in the clinic. Biliary cystadenoma is a rare, mostly benign neoplasm of the biliary tract that should be considered in the differential diagnosis of cystic lesions of the biliary tract.