Management of Congenital Bile Duct Cysts

Bile duct cysts (BDC) are rare congenital anomalies of the biliary tree that are characterized by cystic dilatation of the extrahepatic and/or intrahepatic bile ducts. Presence of an anomalous bilio-pancreatic junction allowing pancreatic juice to reflux into the biliary tree is the most widely aetiopathogenic concept currently accepted. BDC are associated with biliary stasis and lithiasis, and the whole biliary epithelium is considered at risk of malignant transformation. Magnetic resonance cholangio-pancreatography is currently the most accurate preoperative imaging study to assess cyst anatomy and classify the disease according to the standard Todani classification. Complete cyst excision with cholecystectomy followed by biliary reconstruction using a Roux-enY hepatico-jejunostomy is the treatment of choice for the extrahepatic component of the disease (type I and IV BDC), but cystic involvement up to the roof of the main biliary convergence represents a real surgical challenge to perform complete resection. The optimal treatment of intrahepatic bile duct dilatations remains controversial, especially for type IV-A BDC. In type V BDC (Caroli’s disease), extent of the liver resection is tailored to intrahepatic disease extent and takes into consideration the presence and severity of underPublished online: April 1, 2010 Prof. Jean-François Gigot, Division of Hepatobiliary and Pancreatic Surgery Department of Abdominal Surgery and Transplantation Saint-Luc University Hospital Hippocrate Avenue, 10, BE–1200 Brussels (Belgium) Tel. +32 2 764 14 61, Fax +32 2 764 89 18, E-Mail gigot @ chir.ucl.ac.be © 2010 S. Karger AG, Basel 0253–4886/10/0271–0012$26.00/0 Accessible online at: www.karger.com/dsu Bile Duct Cysts Dig Surg 2010;27:12–18 13 Classification BDC are classified according to the site (extrahepatic and/or intrahepatic), extent (segmental or complete) and shape (cystic or saccular, fusiform) of the biliary anomaly. Dilatation may occur anywhere throughout the biliary tree. The Todani classification, used as a standard [8] ( fig. 1 ), defined type I (I-A: cystic, I-B: segmental, I-C: fusiform shape) as dilatation of the extrahepatic biliary tree, type II as diverticulum of the supraduodenal extrahepatic biliary tree, type III as dilatation of the intraduodenal portion of the extrahepatic biliary tree (choledochocele) and identified two subtypes IV: type IV-A with both intraand extrahepatic dilatation of the biliary tree and type IV-B with multiple and segmental dilatations of the extrahepatic biliary tree. Type V BDC, originally described by Caroli [2] , corresponds to dilatation strictly limited to the intrahepatic biliary tree without extrahepatic component. Unilobar extension of type V BDC is more frequently encountered (80%) in surgical series, especially on the left side of the liver, but the disease may diffusely involve the entire intrahepatic biliary tree [9] . Type I BDC is the more frequent cyst type encountered (70–90%), followed by type IV-A (10–20%), choledochocele (4%), type II (2–5%) and type V (1%). The distribution of BDC types is similar in adults and children, with the exception of Todani type IV-A BDC which are more frequent in adults [2, 3] : an incidence of 18.9% was reported by Yamaguchi [4] in his collective Japanese review but ranges from 35 to 83% in recently reported adult series [2, 3, 10] . The higher rate of type IV-A BDC in adult patients suggests that, although of a congenital origin, these lesions may progress with time or may develop later in life. Physiopathology Currently, there is no universally accepted aetiology of BDC. For types I–IV BDC, several theories have been proposed, but the most widely accepted hypothesis is the long common channel theory of Babbitt [2, 3] . An anomalous bilio-pancreatic junction (ABPJ) with a common channel longer than 10–15 mm and a pancreatico-biliary junction proximal to the sphincter of Oddi may allow pancreatic juice to reflux into the biliary tree, resulting in increased intraductal pressure that may lead to inflammation and secondary ductal dilatation [2, 3] . This hypothesis is supported by the detection of high concentrations of pancreatic enzymes in the bile of these patients. The incidence of ABPJ ranges from 96 to 100% in paediatric series and from 68 to 94% in adult series [2, 3] . ABPJ may be associated with pancreatic stones or protein plug in the dilated common channel or accessory pancreatic duct leading to increased bile duct obstruction and incidence of acute pancreatitis in these patients [5, 11] . Anatomical or functional obstruction of the distal part of the extrahepatic biliary tree has also been reported as a possible pathophysiological precursor of BDC. Furthermore, the hypothesis of oligoganglionosis in the distal part of the extrahepatic biliary tree has also been advocated. This may result in inadequate bile duct autonomic innervation responsible for dysmotility and functional obstruction of the common bile duct (equivalent to achalasia of the oesophagus or Hirschsprung’s disease of the colon) [2] . Intrahepatic BDC, corresponding to type V in the Todani classification, results from embryological malformation of the ductal plate [12] . These anomalies are responsible for bile ductular proliferation in the ductal plate configuration, which may be apparent microscopically or I II III IV-A IV-B V Fig. 1. Various types of BDC according to Todani’s classification.