Congenital cystic lesions of the biliary tract (CCLBT) are rare congenital biliary pathologies due to an abnormality of the development of ductal plaque during embryogenesis or they may be secondary to abnormalities of the pancreaticobiliary junction. Depending on the time of the stoppage of this development, various conditions may occur, gradually affecting the smaller or larger bile ducts. The objectives of this essay are: to illustrate congenital cystic lesions of the biliary tract on the basis of knowledge of embryologic development; to illustrate the imaging...

Congenital cystic lesions of the biliary tract (CCLBT) are rare congenital biliary pathologies due to an abnormality of the development of ductal plaque during embryogenesis (Congenital Cystic Lesions of the Intrahepatic Bile Ducts, CCLIBD) or they may be secondary to abnormalities of the pancreaticobiliary junction (Congenital Cystic Lesions of the Extrahepatic Bile Ducts, CCLEBD)[1]. As regards the CCLIBD, the caliber of malformed ducts determines the type of ductal plate malformation. If small interlobular bile ducts are affected, Von Meyenburg complex or congenital hepatic fibrosis results....

In Von Meyenburg complex (biliary hamartomas), lesions are usually scattered, multiple and can be solid, cystic, or mixed; "the starry sky” appearance is pathognomonic in Magnetic Resonance Cholangiopancreatography (Fig. 1, Fig. 2). Hepatobiliary contrast agents will demonstrate no communication with the biliary tree. At Ultrasound, small hamartomas are usually echogenic. Often tiny individual hamartomas cannot be resolved and are instead interpreted as diffuse heterogenous liver echotexture. Larger hamartomas (>10 mm) may appear hypoechoic or anechoic and “comet tail artefact” may be seen [9]. Differential diagnosis...

CCLBTs are rare congenital biliary pathologies. The clinical significance of these conditions is varied, ranging from none in biliary hamartomas to high risk of cholangiocarcinoma in Caroli disease and predisposition for cholangitis, pancreatitis and malignancy in choledochal cysts. CCLBTs can be recognized with characteristic radiological features, using almost all the diagnostic techniques. Familiarity with imaging findings is crucial for their appropriate detection and for differential diagnosis with other similar hepatic cystic lesions (from simple hepatic cysts to metastatic lesions).

Mariangela Dimarco, [email protected] Dario Giambelluca, [email protected]

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