Hepatobiliary and Pancreatic: Cystic bile duct remnant after surgery for a choledochal cyst

Abstract

Choledochal cysts are congenital anomalies of the bile duct that result in dilatation of the extrahepatic bile duct, the intrahepatic bile ducts or both components of the biliary system. Although several forms of dilatation have been described including bile duct diverticula, the most common is diffuse dilatation of the extrahepatic bile duct. The majority of these patients also have an anomalous junction of the bile duct and main pancreatic duct creating a “long common channel”. At least 50% of patients are diagnosed before the age of 10 years because of abdominal pain, jaundice, pancreatitis or a palpable abdominal mass. However, 25% of patients present as adults, usually with abdominal pain, pancreatitis or abnormal liver function tests. The diagnosis is readily made on an ultrasound study but additional investigations can include computed tomography (CT) scans, magnetic resonance imaging (MRI) scans and endoscopic retrograde cholangiopancreatography. The treatment of choice is usually surgical excision of the cyst with a biliary reconstruction using a choledochojejunostomy. Complications of untreated choledochal cysts include biliary cirrhosis, portal hypertension and the development of cholangiocarcinoma. Complications after surgery can include a cystic bile duct remnant as illustrated below. The patient was a 48-year-old woman who was admitted to our hospital with upper abdominal pain. Her past history included excision of a choledochal cyst at the age of 8 years. She was investigated with an enhanced CT scan, MRI scan (T2 weighted) and magnetic resonance cholangiopancreatography (MRCP). The CT scan (Figure 1, left) and MRCP (Figure 1, right) show a cystic structure in the head of the pancreas with a filling-defect, 15 mm in diameter. Various tumor markers were within the reference range. At laparotomy, there was a dilated remnant of the bile duct in the head of the pancreas (Figure 2, left). This was resected down to the junction with the main pancreatic duct. The bile duct remnant contained a calculus (Figure 2, right) while histological examination of the wall of the sac only revealed chronic inflammatory tissue. The patient has been followed for 12 months since surgery and is currently painfree. The management of enlarged but asymptomatic bile duct remnants is less clear although there are case reports of the development of bile duct cancer.