*Magdalena, Sonora, México, ^# Parana, Rio Negro City, Brazil

Definition: Cystic dilatation of the biliary track. The following forms are usually recognized⁷:

• Type I: cystic dilatation of the extrahepatic bile duct with normal intrahepatic bile ducts (most common - 70 to 80%)
• Type II: diverticulum of the common bile duct (rare)
• Type III: intrapancreatic diverticulum of the distal common bile duct or choledococele (rare)
• Type IV: cystic dilatation of the extrahepatic and intrahepatic bile ducts (second most common form).
• Type V: cystic dilatation of the intrahepatic bile ducts with normal extrahepatic bile duct (also called Caroli’s disease)
• Form fruste: combines dilatations of both intra- and extrahepatic ducts.

Synonyms: Choledococele, biliary diverticulum

Incidence: Choledochal cyst is a rare congenital anomaly that occurs in approximately 0.005:10,000 live births^[1]. It is more common in females (M1:F1.5^[2]-3.5) and among Asian.

Recurrence risk: None.

Etiology: Unknown. The theory proposed by O’Neil There are many theories that try to explain the etiology of the choledochal cyst:

• Embryologic anomalies of the growth of the hepatic diverticulum^[3],^[4].
• Obstruction of the distal common bile duct during fetal development resulting in weakness of the choledochal wall which responsible for the development of the choledochal cyst^[5]. This obstruction could be due to:
  • congenital stenosis,
  • persistence of epithelial membrane,
  • abnormal valves
  • neuromuscular incoordination of the sphincter^[6] or
  • agangliosis of the distal bile duct^[7].
• The choledochal cyst could also be due to an anomalous arrangement of the pancreatic or biliary duct system^[8][9]. An abnormal angle of entry of the pancreatic duct into the ampulla of Vater could allow pancreatic enzyme reflux to reach the common bile duct, causing some damage to it in utero^[10]. This theory is being abandoned because the choledochal cyst can be diagnosed before the exocrine function of the pancreas begins^[11].

Diagnosis: Right upper quadrant cyst.

Ultrasound appearance: The ultrasound diagnosis can be made in the second and third trimesters of pregnancy and cases have been reported as early as 15 weeks" gestation^{[12], [13], [14], [15]}. The recognition is important for the early postnatal evaluation and treatment since unrecognized biliary tract obstruction due to choledochal cysts or biliary atresia can result in significant morbidity and mortality (hepatic fibrosis, cholangitis, portal hypertension)^[16]. The characteristic finding is a simple anechoic cyst in the upper abdomen very close to the porta hepatis^[17], but it can be seen next to the right and left hepatic ducts or joining by a duct to the gallbladder. Certain diagnosis is established when a communication between the bile duct and the cyst can be visualized^[18]. When Doppler is used, it can show a relationship between the portal vein, hepatic artery and the umbilical vein, as well as the absence of flow inside the cyst.

The following images from Dr. Luis Goncalves are from the Case of the Week #28.

Genetic anomaly: None known currently.

Differential diagnosis: A cystic mass in the right upper quadrant can be due to:

• duodenal duplication^[19],
• duodenal atresia,
• duplication cyst of the pylorus^[20],
• congenital biliary atresia^{[21], [22]},
• gallbladder duplications,
• hepatic or
• omental cysts^[23],
• adrenal cysts,
• renal cysts,
• mesenteric cysts,
• ovarian cysts and
• lymphangiomas.

Associated anomalies: Biliary obstruction or atresia (40%)²,^[24], congenital hepatic fibrosis, liver cirrhosis², Trisomy 18². By far the most important anomaly to exclude Postnatally is biliary atresia since the Kasai procedure is more successful when performed early in life^[25].

Prognosis: The mortality and morbidity are associated with:

• biliary atresia,
• prolonged bile stasis,
• biliary cirrhosis,
• cholangitis,
• delayed surgery,
• gastric outlet obstruction^[26]
• multiple anomalies^[27].

The prognosis is excellent when treated early.

Management: Prenatal: No alteration in the obstetrics management. Fetal surgery is not advised and the anomaly must be surgically treated after birth ^[28]. Prenatal diagnosis is useful in preventing important postnatal complications. Postnatal: The possibility of biliary obstruction (jaundice) must be assessed after birth. Gastric outlet obstruction may require immediate intervention²⁴. Surgeries typically performed after birth include the Kasai procedure (hepaticojejunostomy) for biliary atresia, retrocolic Roux-en-Y choledocho- or hepatico-jejunostomy with an antireflux valve² or simply excision of the cyst.

References:

^[1] Dewbury KC, Alewthore APR, Birch SJ, et al. Prenatal ultrasound demonstration of choledochal cyst. Br J Radiol 1980;53:906-907

^[2] Cheng MT, Chang MH, Hsu HY, Ni YH, Lai HS, Chen CC, Chen WJ, Hsieh FJ, Chu JS Choledochal cyst in infancy: a follow-up study. Chung Hua Min Kuo Hsiao Erh Ko I Hsueh Hui Tsa Chih 2000 Jan-Feb;41(1):13-7

^[3] Barlow B, Tabor E, Blane WA, et al. Choledochal cyst: a review of 19 cases. J Pediatr 1976, 9, 934-938;

^[4] Martin I, Rowe G. Portal hypertension secondary to choledochal cyst. Ann Surg 1979; 190:638-642

^[5] Miyano F, Suruga K, Chen SC. A clinicopathologic study of choledochal cyst. World J Surg 1980;4:431-438; Splitz I. Experimental production of cystic dilatation of the common bile duct in neonatal lambs. J Pediatr Surg  1977, 12:39-42

^[6] Ito T, Ando H, Nagaya N, et al. Congenital dilatation of the common bile duct in children –the etiologic significance of the narrow segment distal to the dilated common bile duct. Z. Kinderchir 1984; 39:40-45

^[7] Kusanoki M, Saltoh N, Yamamusa T, et al. Choledochal cysts and oligoganglionosis in the narrow portion of the choledochos. Arch Surg 1988; 124:984-986

^[8] O"Neill JA Jr, Templeton JM Jr, Schnaufer L, Bishop HC, Ziegler MM, Ross AJ 3d. Recent experience with choledochal cyst. Ann Surg. 1987 May;205(5):533-40.

^[9] Todani T, Wattanake Y,  Narusume M, et al. Congenital bile duct cysts classification, operative procedures, and review of 37 cases including cancer arising from choledochal cyst. Am J Surg1977; 134:263-269

^[10] Oguchi Y, Okada A, Nakamura T, et al. Histopathologic studies of dilation of the bile ducts as related to an anomalous junction of the pancreaticobiliary system: clinical and experimental studies. Surgery 1988; 103:168-173

^[11] Schroeder D, Smith L, Prain C. Antenatal diagnosis of choledochal cyst at 15 weeks gestation etiologic implications and management. J Pediatr Surg 1989;24:936-938

^[12] Greenholz SK.Antenatal diagnosis of choledochal cyst at 15 weeks" gestation: etiologic implications and management. J Pediatr Surg 1990 May;25(5):584

^[13] Schroeder D, Smith L, Prain HC. Antenatal diagnosis of choledochal cyst at 15 weeks" gestation: etiologic implications and management. J Pediatr Surg 1989 Sep;24(9):936-8

^[14] Benhidjeb T, Chaoui R, Kalache K, Mau H, Muller JM. Prenatal diagnosis of a choledochal cyst: a case report and review of the literature. Am J Perinatol 1996 May;13(4):207-10

^[15] Lugo-Vicente HL. Prenatally diagnosed choledochal cysts: observation or early surgery? J Pediatr Surg 1995 Sep;30(9):1288-90

^[16] Gallivan EK, Crombleholme TM, D"Alton ME. Early prenatal diagnosis of choledochal cyst. Prenat Diagn 1996 Oct;16(10):934-7

^[17] Brunero M, De Dreuzy O, Herrera JM, Gauthier F, Valayer L.Prenatal detection of a cyst in the liver hilum. Interpretation for an adequate treatment. Minerva Pediatr 1996 Nov;48(11):485-94

^[18] Faure JM, Deschamps F, Allal H, Boulot P. Choledochal cyst. Prenatal diagnosis and early neonatal management. J Gynecol Obstet Biol Reprod (Paris) 1996;25(7):716-8

^[19] Yamataka A, Pringle KC. A case with duodenal duplication cyst: prenatal diagnosis and surgical management. Fetal Diagn Ther 1998 Jan-Feb;13(1):39-41

^[20] Goyert GL, Blitz D, Gibson P, Seabolt L, Olszewski M, Wright DJ, Schwartz DB. Prenatal diagnosis of duplication cyst of the pylorus. Prenat Diagn 1991 Jul;11(7):483-6

^[21] Matsubara H, Oya N, Suzuki Y, Kajiura S, Suzumori K, Matsuo Y, Suzuki T, Hashimoto T. Is it possible to differentiate between choledochal cyst and congenital biliary atresia (type I cyst) by antenatal ultrasonography? Fetal Diagn Ther 1997 Sep-Oct;12(5):306-8

^[22] Tsuchida Y, Kawarasaki H, Iwanaka T, Uchida H, Nakanishi H, Uno K. Antenatal diagnosis of biliary atresia (type I cyst) at 19 weeks" gestation: differential diagnosis and etiologic implications.  Pediatr Surg 1995 May;30(5):697-9

^[23] Yamataka A, Pringle KC A case with duodenal duplication cyst: prenatal diagnosis and surgical management. Fetal Diagn Ther 1998 Jan-Feb;13(1):39-41

^[24] Ibanez V, Gutierrez C, Vila JJ, Barrios JE, Lluna J, Roca A, Garcia-Sala C. Prenatal diagnosis of biliary atresia associated with choledochal cyst. Cir Pediatr 1996 Oct;9(4):135-7

^[25] Gallivan EK, Crombleholme TM, D"Alton ME Early prenatal diagnosis of choledochal cyst. Prenat Diagn 1996 Oct;16(10):934-7

^[26] Hamada Y, Tanano A, Sato M, Kato Y, Hioki K Rapid enlargement of a choledochal cyst: antenatal diagnosis and delayed primary excision. Pediatr Surg Int 1998 Jul;13(5-6):419-21

^[27] Cheng MT, Chang MH, Hsu HY, Ni YH, Lai HS, Chen CC, Chen WJ, Hsieh FJ, Choledochal cyst in infancy: a follow-up study.Chung Hua Min Kuo Hsiao Erh Ko I Hsueh Hui Tsa Chih 2000 Jan-Feb;41(1):13-7

^[28] Rha SY, Stovroff MC, Glick PL, Allen JE, Ricketts RR. Choledochal cysts: a ten year experience. Am Surg 1996 Jan;62(1):30-4