Choledochal cysts and fibropolycystic disease
- Lesion
Some people are born with bile ducts that are too wide, cystic or scarred; these can block bile, get infected or turn malignant.
What it is
Developmental anomalies of the bile ducts form two groups. Choledochal cysts are congenital dilations of the common bile duct, often with an abnormal pancreaticobiliary junction. Fibropolycystic diseases arise from faulty remodelling of the ductal plate: von Meyenburg complexes, Caroli disease, congenital hepatic fibrosis and polycystic liver disease. Many are linked to polycystic kidney disease. Several raise the risk of cholangitis, stones and cholangiocarcinoma.
Step by step
- In the embryo, a ductal plate of biliary cells forms around each portal vein branch.
- Normally the plate is remodelled into tubular ducts and the excess is removed.
- Defective cilia proteins (fibrocystin in ARPKD, polycystins in ADPKD) disturb this remodelling.
- Persistent ductal plate remnants become dilated, cystic or surrounded by fibrous tissue.
- Stagnant bile in dilated ducts favours stones, infection and, over time, dysplasia.
Biliary structural anomalies
| Anomaly | What it is | Associations and risks |
|---|---|---|
| Choledochal cyst | Cystic dilation of the common bile duct (several types) | Abnormal pancreaticobiliary union; stones, cholangitis, pancreatitis, cholangiocarcinoma |
| Von Meyenburg complex | Small clusters of dilated ducts with bile in fibrous stroma | Usually incidental; seen with polycystic disease |
| Caroli disease | Saccular dilation of large intrahepatic ducts | Stones, cholangitis, abscesses, cholangiocarcinoma |
| Congenital hepatic fibrosis | Wide fibrous portal bands with irregular duct profiles | ARPKD; presinusoidal portal hypertension |
| Polycystic liver disease | Many cysts lined by biliary epithelium | ADPKD (PKD1, PKD2) or isolated forms |
Test yourself
Think of the answer, then tap the question to see it.
What developmental error underlies the fibropolycystic liver diseases?
Faulty remodelling of the embryonic ductal plate, often due to defects in ciliary proteins.
What is Caroli syndrome?
Caroli disease (saccular dilation of large intrahepatic ducts) together with congenital hepatic fibrosis.
Which cancer risk is raised in choledochal cysts?
Cholangiocarcinoma, which is why the cyst is usually removed.
Elsewhere in DurgiPedia
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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Cholangitis (StatPearls (NCBI Bookshelf), 2023).
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Representative model, for educational purposes only.