Choledochal Cysts

Choledochal cyst is a congenital dilatation of part or whole of the bile duct. The cystic dilatations of the biliary tree can involve the extrahepatic and/or the intrahepatic biliary tract. There are five major classes of choledochal cysts:¹

• Type I cysts (80-90% of all choledochal cysts) consist of saccular or fusiform dilatations of part or all of the extrahepatic bile duct.
  • Type IA is saccular and involves all or most of the entire extrahepatic bile duct.
  • Type IB is saccular and involves a limited segment of the bile duct.
  • Type IC is more fusiform and involves all or most of the extrahepatic bile duct.
• Type II choledochal cyst is an isolated diverticulum protruding from the wall of the common bile duct or joined to the common bile duct by a narrow stalk.
• Type III choledochal cyst (choledochocoele) arises from the intraduodenal portion of the common bile duct.
• Type IV:
  • Type IVA cysts consists of multiple dilatations of the intrahepatic and extrahepatic bile ducts.
  • Type IVB choledochal cysts are multiple dilatations involving only the extrahepatic bile ducts.
• Type V (Caroli disease) consists of multiple dilatations limited to the intrahepatic bile ducts.²

• Choledochal cysts are relatively rare in Western countries. Reported frequency rates range from 1 case per 100,000-150,000 to 1 case per 2 million live births.
• Choledochal cysts are much more prevalent in Japan and China. Approximately 33-50% of reported cases come from Japan, where the frequency in some series approaches 1 case per 1000 population.³
• Choledochal cysts are 3 or 4 times more prevalent in females than males.
• Most patients with choledochal cysts are diagnosed during infancy or childhood, although the condition may be discovered at any age. Approximately 67% of patients present before the age of 10 years.

• Classically cause intermittent abdominal pain, jaundice, and a right upper quadrant abdominal mass. However this classic triad is only found in a minority of patients.
• Infants:
  • Infants frequently present with jaundice and pale stools.
  • Often have a palpable mass in the right upper quadrant of the abdomen, associated with hepatomegaly.
• Older children:
  • Typically present with intermittent biliary obstruction or recurrent bouts of pancreatitis.
  • May also present with a palpable right upper quadrant mass and jaundice.
  • Children who mainly present with pancreatitis frequently have only intermittent attacks of colicky abdominal pain.
• Adults:
  • Frequently present with vague epigastric or right upper quadrant pain with jaundice or cholangitis.
  • The most common symptom in adults is abdominal pain.
  • Adults with choledochal cysts can present with one or more severe complications, e.g. hepatic abscesses, cirrhosis, portal hypertension, recurrent pancreatitis, gallstones, cholangiocarcinoma.

• Bile duct tumours
• Biliary obstruction
• Cholangiocarcinoma
• Acute pancreatitis

• Raised white blood cell count, (increased immature neutrophils in patients with cholangitis).
• Abnormal liver function tests - cholestasis.
• Serum amylase and lipase concentrations may be increased in the presence of pancreatitis. Serum amylase concentrations also may be elevated in biliary obstruction and cholangitis.
• Abdominal ultrasonography is the test of choice for the diagnosis. Antenatal ultrasound can demonstrate a choledochal cyst as early as 12 weeks gestation.⁴
• Abdominal CT scan and MRI help to delineate the anatomy of the lesion and of the surrounding structures. They can also help to identify the presence and extent of intrahepatic duct involvement.
• Percutaneous transhepatic cholangiography (PTC) or endoscopic retrograde cholangiopancreatography (ERCP) are helpful in demonstrating the presence of an anomalous pancreatobiliary junction and in identifying associated extrahepatic or intrahepatic strictures and stones.⁵

There is a common association with anomalous pancreaticobiliary duct junction.⁶

• Choledochal cysts should be treated by complete surgical excision because of the risk of bile duct malignancy. A biliary-enteric anastomosis restores continuity with the gastrointestinal tract.
• Partial cyst resection and internal drainage is less satisfactory because of occasional pancreatitis, cholangitis, and cholangiocarcinoma.⁷
• Patients who present at a late stage, after the development of advanced cirrhosis and portal hypertension, may not be good candidates for surgery because of the associated high morbidity and mortality rates.
• Patients who present with cholangitis should be treated with broad-spectrum antibiotic therapy directed against common biliary pathogens, e.g. E. coli and Klebsiella spp.¹

• Adults in whom subclinical ductal inflammation and biliary stasis may have been present for years may present with one or more severe complications.
• With increasing age at presentation, the risks of intrahepatic strictures and stones, segmented hepatic atrophy/hypertrophy, secondary biliary cirrhosis, portal hypertension, liver failure and biliary malignancy all increase significantly.⁸
• The reported incidence of cholangiocarcinoma in patients with choledochal cyst ranges from 2.5-26%.⁹
• Postoperatively, patients are at risk of developing pancreatitis and ascending cholangitis.¹⁰

• The prognosis after excision of a choledochal cyst is usually excellent, provided that it is diagnosed early, no complications have developed and cyst excision is complete.