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