KEY FACTS
Terminology
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5 types, but cystic dilation of common bile duct (CBD) is most common type seen in utero
Imaging
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Upper abdominal cyst associated with liver
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Represents markedly dilated CBD
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Adjacent to but separate from gallbladder
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Color Doppler shows relationship to porta hepatis
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Helps rule out vascular mass or vascular malformation
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Look for connections to hepatic ducts
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Coronal view is best
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Cyst grows with advancing pregnancy
Top Differential Diagnoses
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Umbilical vein varix: Color Doppler shows flow
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Gallbladder duplication: Sac-like, less tubular
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Liver cyst: Can occur anywhere in liver
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Liver tumors: Often solid or mixed cystic/solid
Clinical Issues
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Most often incidental finding at time of anatomy scan
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1/3 of all cases are from Japan
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1:1,000 incidence in Asia
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1:100,000 incidence outside Asia
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Treatment and prognosis
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Better outcome with early diagnosis and treatment
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Untreated leads to cholestasis, biliary cirrhosis, and liver failure
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Surgical resection with biliary-bowel anastomosis
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Scanning Tips
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Look for gallbladder in every case with liver anomaly
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Can be routinely seen in 2nd trimester
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Do not confuse choledochal cyst with gallbladder
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3D ultrasound may be helpful
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Multiplanar images to look at all margins of cyst for biliary connections
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