Classification of choledochal cyst with MR cholangiopancreatography in children and infants: special reference to type Ic and type IVa cyst

Transcription

1 Classification of choledochal cyst with MR cholangiopancreatography in children and infants: special reference to type Ic and type IVa cyst Poster No.: C-1333 Congress: ECR 2011 Type: Educational Exhibit Authors: A. S. Littooij, M. V. Fortier; Singapore/SG Keywords: Pediatric, Abdomen, Biliary Tract / Gallbladder, MR DOI: /ecr2011/C-1333 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 15

2 Learning objectives In this poster, we illustrate the different types of choledochal cysts seen in a pediatric population and outline the importance of differentiating between dilatation of the intrahepatic ducts due to either obstruction or extention of choledochal cyst. The diagnostic features that can help in making the accurate diagnosis will be described. Background Choledochal cysts are congenital dilatations of the biliary tree usually found in infancy or childhood. The incidence is much higher in Asia (Fig 1) and is approximately three times more frequent in females. Only 20% of the cases will present with the classical triad of abdominal pain, palpable mass and jaundice. Choledochal cysts are usually classified according to Todani into five types (Fig 2): Type I, occuring up to 80-90% of the cases, consists of dilatation of the extrahepatic bile ducts. This dilatation may be cystic (Type 1a), focal (Type Ib) or fusiform (Type 1c). Type II describes a diverticulum in the CBD. Type III, also called choldochocele, is a focal dilatation of the distal common bile duct in the papillary region into which the pancreatic ducts drain. Type IVa shows multiple dilatations in the extra and intrahepatic bile ducts, whereas type IVb represents multiple dilatations in only the extrahepatic bile duct. Type V is synonymous with Caroli disease. The choledochal cysts seen in the pediatric population are type I and IVa cysts. These cysts are highly associated with an abnormal junction of the common bile duct with the pancreatic duct and this is generally accepted as the cause of it. The abnormal anomalous pancreaticobiliary union (APBU) is characterized by fusion of pancreatic duct and common bile duct outside the duodenal wall, with formation of a long common channel, usually more than 15mm (Fig 3 and 4). This APBU allows reflux of pancreatic enzymes into the biliary tract causing cholangitis with subsequent dilatation of the bile duct. The standard classification system for choledochal cysts is based on the cholangiographic morphology, location and number of extrahepatic and intrahepatic bile duct dilatations. This classification is confusing because it includes distinct disease entities such as Caroli's disease, diverticulum and choledochocele. Furthermore, the distinction between type I and IVa is arbitrary for the intrahepatic ducts are seldom completely normal, suggesting they are variations of the same disease entity and defining is arbitrary. Page 2 of 15

3 Complications of untreated choledochal cysts of varying severity are reported ranging from lithiasis and infection to cyst rupture (Fig 5), biliary cirrosis and cholangiocarcinoma. The initial imaging modality of choice is ultrasound often followed by MR cholangiopancreatography (MRCP). MRCP provides accurate preoperative evaluation to plan for total cyst resection. Resection and Roux-en-Y hepaticojejunostomy (Fig 6) is the management of choice. With this only the extrahepatic cyst is removed. In type IVa cyst, the intrahepatic disease remains and is prone to bile stasis, stone/sludge formation and cholangiocarcinoma. These risks are alleviated by wide hilar anastomosis. Localized intrahepatic disease may be treated by segmental hepatic lobectomy. Images for this section: Fig. 1: Table 1 Page 3 of 15

4 Fig. 2: Choledochal cysts - Todani's Classification Page 4 of 15

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6 Fig. 3: The pancreaticobiliary union Page 6 of 15

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8 Fig. 4: 6 year old girl presented with abdominal pain. MRCP shows choledochal cyst with intrahepatic extention and minor strictures (red arrow) in the hepatic hilum. Common channel with stones (yellow arrow) is identified. Fig. 5: 7 year old boy presented with abdominal pain and fever. MRCP (a-c) shows choledochal cyst with obstruction (red arrow). Periportal edema and gallbladder wall thickening (yellow arrow) suggest cholangitis and cholecystitis. US (d-f) 2 days later revealed decrease in dilatation of the biliary tract with # ascites, representing cyst rupture. The cholangiogram (g) after conservative treatment shows type IVa cyst without contrast lekkage. Page 8 of 15

9 Fig. 6: Treatment of choledochal cysts: complete resection and hepaticojejunostomy Page 9 of 15

10 Imaging findings OR Procedure details Generally, the type Ic cysts are defined as fusiform dilatation of the common bile duct and common hepatic duct without involvement of the intrahepatic bile ducts (Fig 1). When there is associated obstruction due to calculi and/or sludge, dilatation of the intra-hepatic ducts is often seen (Fig 2). This can lead to confusion with type IVa cysts that show multiple cystic dilatations of extra- and intra-hepatic bile ducts due to strictures (Fig 3). To differentiate between type Ic and type IVa cyst it is important to demonstrate the obstructing calculus, looking for signs of obstruction, such as dilatation of the pancreatic duct and hydrops of the gallbladder as well as to correlate findings with biochemical markers (Fig 2). Identifying a ductal stricture can have important implications. Such a stricture is characteristic of type IVa cysts (Fig 4) and determines surgical management, especially when located around the hepatic hilum, because this stricture can be corrected by portal dissection of the liver to obtain a large anastomosis. Identifying such as stricture is therefore more important than classifying the cyst correctly as type Ic or IVa. Images for this section: Fig. 1: Type 1 choledochal cyst Page 10 of 15

11 Fig. 2: Type IVa or Type Ic Choledochal cyst? 2 ½ year old boy presenting with jaundice. US (a,b) and MRCP (c,d) show choledochal cyst with intrahepatic dilatation & obstruction. Intra-operative cholangiogram (e) after stone removal, revealed decrease in intrahepatic dilatation. Diagnosis? Page 11 of 15

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13 Fig. 3: 6 year old girl presented with abdominal pain. MRCP shows choledochal cyst with intrahepatic extention and minor strictures (red arrow) in the hepatic hilum. Common channel with stones (yellow arrow) is identified Fig. 4: 3 years old girl, presented with abdominal pain and vomiting MRCP shows choledochal cyst with intrahepatic extention and strictures Page 13 of 15

14 Conclusion Choledochal cysts are rare congenital dilatations of the biliary tree. They require preoperative evaluation to plan for total cyst resection, generally by means of MRCP. The most common used classification is devised by Todani et al. We believe that this classification system is confusing as it includes distinct disease entities with different etiology, prognosis and therapy. Futhermore, differentiation between the congenital choledochal cysts seen in the pediatric population is arbitrary as the intrahepatic bile ducts are seldom completely normal. Therefore, differentiation between intrahepatic extention due to obstruction or extention of the choledochal cyst is challenging. Detecting a ductal stricture in the hepatic hilum is most important, because this stricture changes operative management. Personal Information Annemieke S. Littooij Department of Diagnostic Imaging KK Women's and Children's Hospital Singapore 100 Bukit Timah Road Singapore alittooij@hotmail.com Marielle V. Fortier Department of Diagnostic Imaging KK Women's and Children's Hospital Singapore 100 Bukit Timah Road Singapore Marielle.Fortier@kkh.com.sg Page 14 of 15

15 References - Todani, Watanabe Y, Narusue M, Tabuchi K, Oka jima K. Congenital bile duct cysts: classifiaction, operative procedures and review of thirty-seven cases including cancer arising form choledochal cyst. J. Surg 1977;147: Mortele KJ, Rocha TC, Streetr JL, Taylor AJ. Multimodality imaging of pancreatic and biliary congenital anomalies. Radiographics 2006;26: Visser BC, Suh I, Way LW, Kang SM. Congenital choledochal cysts in adults. Arch Surg 2004; 139 (8): Kim MJ, Han SJ, Kim JH, Oh JT, Chung KS, Yoo HS. Using MR Cholangiopancreatography to reveal anomalous pancreaticobiliary ductal union in infants and children with choledochal cysts. AJR 2002; 179: Chavhan GB, Babyn PS, Manson D, Idarsson LV. Pediatric MR Cholangiopancreatography:Principles, technique,and clinical applications. Radiographics 2008; 28: Page 15 of 15