Type VI choledochal cyst diagnosed on ERCP with direct cholangioscopy

摘要

Choledochal cysts are rare congenital dilations of the biliary system. They are more common in East Asia than in the West. Choledochal cysts have been traditionally classified into 5 types.1Todani T. Watanabe Y. Narusue M. et al.Congenital bile duct cysts: classification, operative procedures, and review of thirty-seven cases including cancer arising from choledochal cyst.Am J Surg. 1977; 134: 263-269Abstract Full Text PDF PubMed Scopus (1147) Google Scholar A 6th type of choledochal cyst has been described as either a cyst arising off the cystic duct or a dilation of the cystic duct (Fig. 1). Data on type VI choledochal cysts are limited, with fewer than 25 cases reported. Malignant transformation of these cysts has been described; from a review of the literature, malignancy was found in 2 of 15 adult patients and 0 of 9 pediatric patients.2Bode W.E. Aust J.B. Isolated cystic dilatation of the cystic duct.Am J Surg. 1983; 145: 828-829Abstract Full Text PDF PubMed Scopus (31) Google Scholar, 3Champetier P. Partensky C. Ponchon T. Cystic malformations of the cystic duct.Surg Radiol Anat. 1987; 9: 287-291Crossref PubMed Scopus (10) Google Scholar, 4Kise Y. Uetsuji S. Takada H. et al.Dilatation of the cystic duct with its congenital low entry into the common hepatic duct.Am J Gastroenterol. 1990; 85: 769-770PubMed Google Scholar, 5Serena Serradel A.F. Santamaría Linares E. Herrera Goepfert R. Cystic dilatation of the cystic duct: a new type of biliary cyst.Surgery. 1991; 109: 320-322PubMed Google Scholar, 6Bresciani C. Gama-Rodrigues J. Santos V.R. Video-laparoscopic treatment of a sizeable cyst of the cystic duct: a case report.Surg Laparosc Endosc. 1998; 8: 376-379Crossref PubMed Scopus (15) Google Scholar, 7Loke T.K. Lam S.H. Chan C.S. Choledochal cyst: an unusual type of cystic dilatation of the cystic duct.AJR Am J Roentgenol. 1999; 173: 619-620Crossref PubMed Scopus (36) Google Scholar, 8Conway W.C. Telian S.H. Wasif N. et al.Type VI biliary cyst: report of a case.Surg Today. 2009; 39: 77-79Crossref PubMed Scopus (20) Google Scholar, 9Chan E.S. Auyang E.D. Hungness E.S. Laparoscopic management of a cystic duct cyst.JSLS. 2009; 13: 436-440PubMed Google Scholar, 10Yoon J.H. Magnetic resonance cholangiopancreatography diagnosis of choledochal cyst involving the cystic duct: report of three cases.Br J Radiol. 2011; 84: e18-e22Crossref PubMed Scopus (22) Google Scholar, 11De U. Das S. Sarkar S. Type VI choledochal cyst revisited.Singapore Med J. 2011; 52: e91-e93PubMed Google Scholar, 12Maheshwari P. Cystic malformation of cystic duct: 10 cases and review of literature.World J Radiol. 2012; 4: 413-417Crossref PubMed Google Scholar, 13Shah O.J. Shera A. Shah P. et al.Cystic dilatation of the cystic duct: a type 6 biliary cyst.Indian J Surg. 2013; 75: 500-502Crossref PubMed Scopus (15) Google Scholar The overall rate of malignancy ranges from 5% to 7.5%, with the highest rates reported in types I and IV, and the lowest rates in types II and III.14Ten Hove A. de Meijer V.E. Hulscher J.B.F. et al.Meta-analysis of risk of developing malignancy in congenital choledochal malformation.Br J Surg. 2018; 105: 482-490Crossref PubMed Scopus (42) Google Scholar Type VI choledochal cysts are typically managed with cholecystectomy. The definitive diagnosis of type VI choledochal cysts is usually made intraoperatively; the differentiation between type VI and type II cysts can be challenging on preoperative imaging. Here we present the case of a type VI choledochal cyst diagnosed by ERCP with direct cholangioscopy, allowing for preoperative planning for laparoscopic cholecystectomy, instead of cyst resection with bile duct reconstruction by means of Roux-en-Y hepaticojejunostomy appropriate for a type II choledochal cyst. A 62-year-old Korean woman was evaluated for abdominal pain. Her liver function test results were as follows: alkaline phosphatase 84 U/L, aspartate aminotransferase 20 U/L, alanine aminotransferase 12 U/L, and total bilirubin 0