Introduction:
Choledochal cysts are infrequent congenital malformations characterized by cystic dilatations of the biliary tree that was first described by Vater and Ezler in 1723(1). These dilatations can be extra-hepatic, intrahepatic or both and in this case, it was extra-hepatic. The incidence of choledochal cysts in Asian population is 1 in 1000 live births with predominance in females(2). In western countries, the incidence ranges from 1:100,000 to 1:150,000 in the United States, 1 in 2 million in the United Kingdom. In Africa, there is insufficient data documented about giant choledochal cysts. More than 60% present in the 1st year of life and 20% in the adulthood(3).
Initial classification by Alonso-Lej et al.in 1959 described 3 types of choledochal cysts, type I-III(4). In 1977, Todani and others modified the original Alonso-Lej classification to include type IV and V (Figure 1). Type I of choledochal cysts are further sub-classified into 3 types. Type IA, cystic dilatation of entire extra-hepatic biliary tree, type IB is focal, segmental dilatation of extra-hepatic biliary tree and type IC is fusiform dilatation of entire extra-hepatic biliary tree. Type II describes discrete extra-hepatic bile duct diverticulum while type III often has bulging into duodenal lumen(choledochocele).Type IV A multiple sites of dilatation, both extra and intrahepatic biliary tree and Type IVB has multiple sites of dilatation of extra-hepatic bile duct only while type V has cystic dilatation of only intrahepatic biliary tree(Caroli disease) (5).
Choledochal cysts in children and adults behave differently with type I being common in children and type IV in adults. Anomalies of pancreatic duct and other associated hepatobiliary problems are more seen in adults than in children(6). No strong unifying etiological theory exits for choledochal cysts but some series published by Miyayo and yamataka in 1977, documented an anomalous junctions in 90-100% of patients with choledochal cysts(7). This abnormal communication allows the mixing of bile and pancreatic juices activating pancreatic pro-enzymes that later damages and weakens the bile duct wall resulting in formation of choledochal cysts (8).
The primary diagnostic modality is by abdominal ultrasound scan followed by CT scan and the MRI. The associated anomalies are biliary atresia, gallbladder atresia, hepatic fibrosis and those of pancreatico-biliary ductal system. ERCP and MRCP have a conclusive role in confirming ultrasound scan diagnosis. This is also done to evaluate anatomy and identify complications related to the cyst(5). In this case, a CT scan was done to confirm type IA giant choledochal cyst.
This choledochal cyst is usually associated with complications that range from cholecystitis, cholangitis, pancreatitis, stone formation and malignancy. Prevalence of biliary malignancy is found to be around 30% of the cases, this increase with age and is commonly higher in those with type I and type IV choledochal cysts(9).
The treatment of choledochal cyst is an initial control of complications then followed by the primary surgery of the cause. Presently the most popular and accepted surgical intervention is by total excision of the choledochal cyst and restore the biliary enteric drainage into the duodenum either via Roux-en-Y hepatico-jejunostomy or Braun hepatico-jejunostomy. The later approach was used in our patient(10).
A laparoscopic approach is also currently being explored since it offers less invasive of the surgical technique approach for the management of choledochal cyst in children (11).
We report a case of a 17 year old female who was diagnosed and managed for a giant choledochal cyst type IA at Mbarara Regional Referral Hospital, Uganda