Authors: Meena Thayu, MD; Michael Nance, MD; Petar Mamula, MDSeries Editors: David A. Piccoli, MD; Petar Mamula, MD

Disclosures

October 19, 2006

Clinical Course and Discussion

The patient underwent excision of the choledochal cyst, cholecystectomy, and reconstruction with a primary choledochoduodenostomy (Figure 3). Her aminotransferase and GGT levels returned to normal, and she has had normal CA (cancer antigen) 19-9 (used to screen for cholangiocarcinoma) levels postoperatively.

Intraoperative view of choledochal cyst.

Choledochal cysts are congenital anomalies of the biliary tract that involve segmental dilatation of the biliary ductal system with either extra- or intrahepatic involvement. The incidence is estimated to be 1/150,000 live births in Western countries, with a higher incidence in Asian countries -- particularly Japan, where the incidence is as high as 1/1000 live births. The female-to-male ratio is 4:1. Recent case series show that these cysts present with equal frequency in adults and children. The etiology of these lesions is multifactorial, and it is believed that genetic and environmental factors predispose to their development. Choledochal cysts evolve from unequal proliferation of biliary epithelial cells prior to bile duct cannulation, with resulting ductal obstruction and/or distension during the prenatal or neonatal period. Choledochal cysts result in an abnormal pancreaticobiliary junction, with a long common channel between the common bile duct and the pancreatic duct seen in 70% of cases. Distal displacement of the ampulla of Vater is also a feature. Reflux of pancreatic enzymes and bile predisposes to biliary epithelial cell damage. The ensuing inflammation and distension cause cyst formation and, eventually, malignant transformation.

Choledochal cysts are stratified into 5 types. Type I cysts involve cystic dilatation of the common bile duct (CBD), and are the most common. Type II cysts involve an isolated diverticulum from the wall of the CBD. Type III cysts feature cystic dilatation limited to the intraduodenal portion of the distal CBD, include a choledochocele, and are lined by biliary or duodenal epithelium. Type IV cysts include multiple dilatations of the intra- and extrahepatic bile ducts. Type V cysts include isolated or multiple cystic dilatations of the intrahepatic bile ducts without extrahepatic involvement. This last type is also known as Caroli's disease.

The clinical presentation of choledochal cysts varies with age. Infants may present with jaundice, abdominal mass, irritability, and vomiting. Older children and adolescents may present with intermittent colicky abdominal pain or biliary obstruction, and recurrent pancreatitis. Adults present with the classic triad of abdominal pain, jaundice, a palpable mass, or, in certain cases, cholangitis. Tools that may aid in the diagnosis include a hepatic function panel, abdominal ultrasound, endoscopic retrograde cholangiopancreatography or MRCP, and endoscopic ultrasound. The pathology is variable. In children, cysts are usually dense and fibrotic with chronic and acute inflammation. In adults, there is often evidence of inflammation, erosions, sparse mucin glands, and metaplasia. Adults may also present with malignancy involving the posterior cyst wall. Treatment includes complete surgical excision of the cyst with primary choledochoduodenostomy or Roux-en-Y choledochojejunostomy. Hepaticojejunostomy may be necessary based on the extent of ductal involvement. Choledochoceles may be amenable to sphincterotomy. Complications include those associated with surgery, pancreatitis, anastomotic strictures, ascending cholangitis, intrahepatic bile duct stones, hepatic abscesses, cirrhosis, portal hypertension, cholelithiasis, and malignancy -- specifically, cholangiocarcinoma. There is a 10% overall risk for cholangiocarcinoma, and regular lifelong screening with the tumor marker CA 19-9 is recommended for all patients.

In summary, this case highlights the importance of considering anatomic lesions such as choledochal cyst in an adolescent patient presenting with abdominal pain, emesis, and increased liver enzyme levels.

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