Choledochal cyst is a congenital abnormality of the biliary tree that results in dilatation of the bile ducts. It is most common in Asia, with various theories proposed for its pathogenesis including abnormalities in bile duct remodeling during embryogenesis or obstruction leading to cyst formation. Patients may present with jaundice, abdominal pain or a mass. Diagnosis is typically made using ultrasound, CT or MRCP imaging. Surgical excision of the cyst and biliary reconstruction is the primary treatment for types I-IV, while type III may be treated endoscopically and type V depends on extent of liver involvement.

1. CHOLEDOCHAL CYST

2. Choledochal cyst
• Focal or diffuse dilatation of biliary tree
• Common congenital abnormality of the biliary
tree
• Most common in Asia with incidence of 1 in
13000 population and common in japan with
an incidence of 1 in 1000
• 60% present in the first decade
• 25% present in adult
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3. Alonso – LEJ/Todani classification
TYPE EXPLANATION
Type I
IA
IB
IC
Classic type, dilatation of CBD, most common 50-80%
Cystic
Fusiform
Saccular
Type II Simple diverticulum of the extrahepatic biliary tree, 2-3%
Type III Cystic dilatation of the intraduodenal portion of CBD, also called
choledochocele, <10%
Type IV
IV A
IV B
Involve multiple cysts of intra and extra-hepatic biliary tree
Both intra and extra-hepatic cysts, 30-40%
Multiple extra-hepatic cysts without intrahepatic involvement <5%
Type V Isolated intrahepatic biliary cystic disease, caroli’s disease, associated
periportal fibrosis or cirrhosis, can be multilobar or confined to single
lobe
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4. 4

5. Pathogenesis
• The cause is unknown. There are theories
proposed.
• Theory I – defect in maturation with ductal plate
malformation.
– Describe development of intrahepatic liver progenitor
cells that are in contact with the mesenchyme of portal
vein and are remodeled intomature ducts.
– Defective bile duct plate remodeling in embryogenesis
results in inflammation and ulceration forming larger
ducts
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6. • Theory II
– Bile duct obstruction or distention in the prenatal
or neonatal period leading to cyst formation
– Obstruction may be secondary to stricture, web ,or
sphincter of Oddi dysfunction
– Pancreatic juice reflux into biliary tree causing
chronic inflammation and increased bile duct
pressure leading to cyst formation
– Animal models
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7. • Theory III
– Most common proposed model for choledochal
cyst
– Related to pancreaticobiliary maljunction
– Defined as an extramural junction of pancreatic
and biliary duct in the duodenum beyond the
intramural sphincter function
– Characterised by long common channel.
– Significant risk for developing
cholangiocarcinoma
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8. Pancreaticobiliary
maljunction
Long common channel
Pancreatic reflux and mixing
with bile
Mixed juice potentially
stagnates in bile tree/gall
bladder
Cycles of inflammation,
activation of proteolytic
enzymes, alteration in bile
composition
Damage to biliary tree
epithelium
Duct distention and may
progress to malignancy
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9. Presentation
• Classic triad of jaundice, abdominal pain and
Rt upper quadrant mass in children
• Infants present with elevated conjugated
bilirubin(80%), failure to thrive or abdominal
mass(30%)
• Abdominal mass becomes less comman with
increasing age
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10. • In adults – abdominal pain, recurrent cholangitis
are more common presentation
• Abdominal pain usually mimics that of calculous
cholecystitis and many individuals may have gall
stones in cyst or in the gall bladder
• May also present with intermittent jaundice, or as
pancreatitis(30%)
• 38% of adults will undergo cholecystectomy
before diagnosis of choledochal cyst.
• Rarely it may present as intraperitoneal rupture or
bleeding due to erosion into adjacent vessels.
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11. Diagnosis
• Requires high suspicion
• Type I cyst may mimics biliary dilatation secondary to
obstruction, difference is elevated ALP in obstruction
• USG is most common first line imaging used in 93% of
pediatric and 72% of adults
• CT is appropriate in adults in whom the differential
diagnosis is broader
• Important consideration in CT is assessing the
hepatobiliary and pancreatic anatomy, with evaluation
of possible biliary malignancy, metastatic disease and
vascular encasement.
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12. • When choledochal cyst is suspected –
visualisation of the pancreatic, extrahepatic
and intrahepatic ductal anatomy is required.
• MRCP is the non-invasive procedure of choice
• Many consider MRCP as the only imaging
required for diagnosis and operative planning.
• Cholangiography is considered gold standard,
can show areas of cystic dilatation, presence of
stone and exclude complete obstruction of bile
duct
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13. Management
• Management of acute symptoms like
pancreatitis, cholangitis, improving general
condition followed by operative management
• Cholecystectomy + complete excision of the
cyst + bile duct reconstruction.
• Type I – complete cyst excision + Roux-en-Y
hepaticojejunostomy reconstruction
• Type II – complete cyst excision + CBD wall
defect closure with or without T-tube
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15. • Type III – primarily treated with ERCP +
endoscopic unroofing of the choledochoceles +
sphincterotomy is done
• Type IV – similar to type I , cholecystectomy +
complete cyst excision + biliary enteric
anastamosis
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16. • Type V – caroli’s disease, begin with conservative
management by treating infection, complications
of drainage, stone extraction antibiotics and
ursodiol
• Single lobe – resection of the parenchyma
involved.
• Bilobar – ursodiol and antibiotics improve bile
flow, in the absence of complications Roux-en-Y
hepaticojejunostomy + b/l transhepatic silastic
stent
• Liver transplant
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