Choledochal cyst is a rare congenital dilatation of the bile duct that occurs in 1 in 100,000 people. It is more common in Asian populations and women. The pathogenesis is typically due to an anomalous pancreaticobiliary junction, where the pancreatic and biliary ducts fuse before entering the duodenum. This allows pancreatic secretions to reflux into the bile duct and cause inflammation and cystic degeneration. Choledochal cysts are classified into 5 types based on their location and extent. Patients typically present with jaundice, right upper quadrant pain, or a palpable mass. Investigations include ultrasound, CT, MRCP and ERCP to establish the diagnosis and classification. Complications include

1. CHOLEDOCHAL CYST

2. EPIDEMIOLOGY
 Less than 1 in 1,00,000
 Common in Asian descent
 Common in women 8:1

3. PATHOGENESIS
 Presence of anomalous pancreatic biliary
junction(APBJ) it is seen in 90% choledochal cysts
 In APBJ pancreatic duct and biliary duct fuse to
form common channel prior to opening in duodenal
wall
 Pancreatic secretions reflux into bile duct which
inflame and damage the biliary tree leading to
cystic degeneration

4. CLASSIFICATION
 Originally classified by Alonso – Lej
 Latter modified by Todani

5.  Type I – extra hepatic fusiform dilatation
most common 60%
 Type II - sacular diverticulum of common bile
duct seen in 5%
 Type III- cystic dilatation of intramural bile
duct with in walls of duodenum
 Type IVa - multiple cystic dilatations in both
intra hepatic and extra hepatic
bile ducts
 Type IVb - multiple cysts limited to extra
hepatic biliary tree seen in 30%
 Type V - multiple intra hepatic cysts only
sometimes may be solitary also
known as Caroli disease

6. PRESENTATION
 Jaundice
 Right upper quadrant pain
 Rarely palpable mass
 Other symptoms like nausea, pruritis, weight
loss, cirrhosis, cholangitis pancreatitis,
hepatic fibrosis, malignancy are reported
during presentation
 Rarely rupture of cyst and bile peritonitis can
also be presented

7. INVESTIGATIONS
 Usually diagnosed when imaging is done for
non specific symptoms
 Ultrasound – dilated cystic lesion which
communicates with the bile duct and is separate
from the gall bladder
 CT scan – diagnosis is suspected
 MRCP – classification can also be done
 ERCP – distal bile duct can also be analysised
which is difficult in MRCP
 Liver function tests – identify cholestatis
jaundice secondary hepatic injury cirrhosis

8. COMPLICATIONS
 Pancreatitis
 Supparative cholangitis
 Gall stone and CBD stone formation
 Rupture of cysts
 Cholangiocarcinoma – seen in 10% to 30%
cases malignant cystic degeneration is
common due to chronic mucosal irritation
from refluxed pancreatic enzymes

9. TREATMENT
 Resection of entire
cyst and appropriate
surgical reconstruction
 Type I – complete
surgical excision
Cholecystectomy and
Roux-En-Y
Hepaticojejunostomy
entire dilated part is
removed

10.  Type II – completely excised if APBJ is involved
enteric diversion with Roux-En-Y
Hepaticojejunostomy is done
 Type III – transduodenal approach for
transduodenal excision or sphincteroplasty in
case of any duodenal or biliary obstruction
 Type IV a – involving one lobe partial
hepatectomy
 Type IV b - extra hepatic cysts treatment as type
I i.e complete surgical excision
Cholecystectomy and Roux-En-Y
Hepaticojejunostomy
 Type V or Caroli’s disease – range from
resection of liver if disease is unilobular to liver
transplantation if disease is diffuse