Choledochal cyst, also known as biliary cyst, is a dilatation of the biliary tree at single or multiple sites in the intra- and/or extrahepatic biliary tree. Alfonso and Todani described the classification of choledochal cysts (CCs) currently utilized today. The pathogenesis of choledochal cyst is proposed to be an abnormal biliopancreatic junction (ABPJ) allowing reflux of pancreatic enzymes into the biliary system. The long channel of the junction, defined as >15 mm from the ampulla of Vater, provides for increased surface area that is exposed to pancreatic enzymes, leading to inflammation, metaplasia, and potential malignancy. In a series by Todani et al., 68% of the malignancies occurred in patients with type I cysts, and 21% occurred in patients with type IV cysts. Current literature suggests the incidence of cancer also increases with age, from around 5% in patients 18–30 years of age to 38% in patients over 60 years of age. Magnetic resonance cholangiopancreatography (MRCP) is the gold standard for diagnosing choledochal cyst, although an ultrasound is often the first-line imaging modality. Complete excision of CC with Roux-en-Y hepaticojejunostomy is the standard of care for most CC given the potential of malignancy.
Choledochal cyst Biliary cyst Cholangiocarcinoma
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