Incidence 1/200,000 live births.
Association w other hepatobiliary disease such as hepatic fibrosis & aberrant pancreatico-biliary duct junction
Presentation usually childhood w jaundice, fever or abdo mass. 25% diagnosed in 1^st yr.

Pathogensis

Possibly caused by anomalous biliary and pancreatic junction, causing pancreas juice to flow backward into bile duct causing cysts to form.

Modified Todani classification

Type I: Fusiform dilation of the common bile duct
Type II: Bile duct diverticulum
Type III: Saccular dilation of the common bile duct in the ampulla, also termed choledochocele
Type IV: Multiple cystic bile duct dilations
- Type IVA: Intra- and extrahepatic cysts
- Type IVB: Extrahepatic cysts only
Type V: Fusiform or saccular cystic dilation of the intrahepatic bile ducts, whether or not associated with hepatic fibrosis (Caroli disease)
Type VI: Isolated cystic dilations of the cyst duct

Initial mx – sepsis with abx, imaging, ERCP +/- stent
Surgical resection to
- Prevent recurrent episodes of sepsis and pain,
- Prevent risk of pancreatitis (passage of debris and calculi)
- Prevent cholangiocarcinoma (Risk of malignancy ~12% or higher)
Type I and IVb
- Complete cyst excision with preservation of pancreatic duct, w hepaticojejunostomy for reconstruction.
- Some recommend liver resection for type IVa with intrahepatic extension for complete removal of cyst, although advantage is debatable.
Type II
- Simple excision
Type III
- Can be treated endoscopically if close to the sphincter with a sphincterotomy
- Otherwise require Pancreatoduodenectomy
Type IVa and V
- Caroli disease,
- Resect if disease localised to one part of liver.
- For others, endoscopic or radiological techniques may be needed to improve biliary drainage.
- Some may need transplant if liver failure.
Intraoperative ultrasound useful to find biliary confluence, intrahepatic extension of cyst and relationship to right hepatic artery above & pancreatic duct below.
Small aberrant ducts may enter cyst, easier to identify once cyst is opened along anterior length.
Segmental ducts incorporated into hepatico-jejunal Roux-en-Y anastomosis.

Surveillance: