Choledochal cyst
Updates to Article Attributes
Choledochal cysts represent congenital disproportionate cystic dilatations of the biliary tree. Diagnosis relies on the exclusion of other conditions as a cause of biliary duct dilatation: (i.e. tumour, gallstone or inflammation as the cause).
Epidemiology
Choledochal cysts are rare, with an incidence of 1:100,000-150,000. Although they may be discovered at any age, 60% are diagnosed before the age of 10 years 1. There is a strong female predilection with a M:F ratio of 1:4. There is a greater prevalence in East Asia.
Clinical presentation
Classically presentation includes the triad of 1:
- abdominal pain
- jaundice
- abdominal mass
This triad is however only present in 19-60% of cases, with palpable mass being the least common manifestation.
Pathology
Their aetiology is uncertain but a close association with anomalous formation of the pancreaticobiliary ductal junction is reported in some subtypes 1. Due to this anomaly, there is a large common channel draining pancreatic and bile duct. Thus the pancreatic juices cause cholangitis and bile duct wall destruction, which together with distal stenosis due to scarring, result in formation of choledochal cyst.
Associations
A number of associations are recognised, including 1:
- biliary atresia
-
hepatic fibrosis
- associated with type V (Caroli disease)
Classification
Commonly accepted classification currently is one devised by Todani et al. There are 5 main types, with several sub typessubtypes some of which can be pathologically unrelated. Briefly:
-
type I: most common, accounting for 80-90%1 (this type can present in utero)
- Ia: dilatation of extrahepatic bile duct (entire)
- Ib: dilatation of extrahepatic bile duct (focal segment)
- Ic: dilatation of the common bile duct portion of extrahepatic bile duct
-
type II: true diverticulum from
extra hepaticextrahepatic bile duct -
type III: dilatation of
extra-hepaticextrahepatic bile duct within duodenal wall (choledochocoele) -
type IV: next most common
- IVa: cysts involving both intra and extrahepatic ducts
- IVb: multiple dilatations/cysts of extra hepatic ducts only
- type V: multiple dilatations/cysts of intra hepatic ducts only (Caroli disease)
The Todani classification scheme has been called into question in surgical literature, with claims that it may unfairly link multiple distinct processes into a spuriously coherent grading scheme 7,8.
The Komi classification classifies choledochal cyst into 3 types based on the anomalous union of the pancreatic-bile duct (AUPBD)2.
Radiographic features
Imaging of the biliary tree can be achieved with ultrasound, CT, direct contrast studies (ERCP, PTC) or MRI.
Ultrasound
Key to the diagnosis is a dilated cystic lesion which communicates with the bile duct and is separate from the gall bladder. Careful search for other causes needs to also be undertaken (see differential below), remaining cognisant that both stone formation and malignancy are associated with choledochal cysts.
CT and MRCP
Findings are similar to US, with a greater ability to demonstrate intrahepatic disease. It is important to remember that with CT IVC the contrast mixing in the cyst may be inhomogeneous. It does however have the advantage that it conclusively demonstrates communication with the biliary tree 1.
Complications
The two most frequent complications of choledochal cysts are stone formation and malignancy. Complications include:
- stone formation: most common
- malignancy
- cholangiocarcinoma
- life time incidence 10-15% 5
- cyst may rupture leading to bile peritonitis
- most frequently seen in neonates 1
- pancreatitis
Treatment and prognosis
The only feasible treatment is surgical excision, with reconstruction. A number of possible approaches exist, depending on cyst location etc... Typically a Roux-en-Y hepaticojejunostomy is performed 1.
Differential diagnosis
General imaging differential considerations include:
- duodenal diverticulum
-
pancreatic cystic lesions
- pseudocyst(s)
- cystic tumours
- other causes of biliary tree dilatation
- impacted gallstone
- cholangiocarcinoma
- biliary stricture
See also
-<p><strong>Choledochal cysts </strong>represent congenital disproportionate cystic dilatations of the <a href="/articles/biliary-tree">biliary tree</a>. Diagnosis relies on the exclusion of other conditions as a cause of biliary duct dilatation: (i.e. tumour, <a href="/articles/gallstone">gallstone </a>or inflammation as the cause).</p><h4>Epidemiology</h4><p>Choledochal cysts are rare, with an incidence of 1:100,000-150,000. Although they may be discovered at any age, 60% are diagnosed before the age of 10 years <sup>1</sup>. There is a strong female predilection with a M:F ratio of 1:4. There is a greater prevalence in East Asia.</p><h4>Clinical presentation</h4><p>Classically presentation includes the triad of <sup>1</sup>:</p><ul>- +<p><strong>Choledochal cysts </strong>represent congenital cystic dilatations of the <a href="/articles/biliary-tree">biliary tree</a>. Diagnosis relies on the exclusion of other conditions as a cause of biliary duct dilatation: (i.e. tumour, <a href="/articles/gallstone">gallstone</a> or inflammation as the cause).</p><h4>Epidemiology</h4><p>Choledochal cysts are rare, with an incidence of 1:100,000-150,000. Although they may be discovered at any age, 60% are diagnosed before the age of 10 years <sup>1</sup>. There is a strong female predilection with a M:F ratio of 1:4. There is a greater prevalence in East Asia.</p><h4>Clinical presentation</h4><p>Classically presentation includes the triad of <sup>1</sup>:</p><ul>
-</ul><p>This triad is however only present in 19-60% of cases, with palpable mass being the least common manifestation.</p><h4>Pathology</h4><p>Their aetiology is uncertain but a close association with anomalous formation of the <a title="Anomalous pancreaticobiliary junction" href="/articles/anomalous-pancreaticobiliary-junction">pancreaticobiliary ductal junction</a> is reported in some subtypes <sup>1</sup>. Due to this anomaly, there is a large common channel draining pancreatic and bile duct. Thus the pancreatic juices cause cholangitis and bile duct wall destruction, which together with distal stenosis due to scarring, result in formation of choledochal cyst.</p><h5>Associations</h5><p>A number of associations are recognised, including <sup>1</sup>:</p><ul>- +</ul><p>This triad is however only present in 19-60% of cases, with palpable mass being the least common manifestation.</p><h4>Pathology</h4><p>Their aetiology is uncertain but a close association with anomalous formation of the <a href="/articles/anomalous-pancreaticobiliary-junction">pancreaticobiliary ductal junction</a> is reported in some subtypes <sup>1</sup>. Due to this anomaly, there is a large common channel draining pancreatic and bile duct. Thus the pancreatic juices cause cholangitis and bile duct wall destruction, which together with distal stenosis due to scarring, result in formation of choledochal cyst.</p><h5>Associations</h5><p>A number of associations are recognised, including <sup>1</sup>:</p><ul>
-</ul><h5>Classification</h5><p>Commonly accepted classification currently is one devised by <em>Todani et al.</em> There are 5 main types, with several sub types some of which can be pathologically unrelated. Briefly:</p><ul>- +</ul><h5>Classification</h5><p>Commonly accepted classification currently is one devised by <em>Todani et al.</em> There are 5 main types, with several subtypes some of which can be pathologically unrelated. Briefly:</p><ul>
-<strong>type I:</strong> most common, accounting for 80-90%<sup>1</sup> (this type can present in utero)<ul>- +<strong>type I:</strong> most common, accounting for 80-90% <sup>1</sup> (this type can present in utero)<ul>
-<strong>type II:</strong> true diverticulum from extra hepatic bile duct</li>- +<strong>type II:</strong> true diverticulum from extrahepatic bile duct</li>
-<strong>type III:</strong> dilatation of extra-hepatic bile duct within duodenal wall (<a href="/articles/choledochocoele">choledochocoele</a>)</li>- +<strong>type III:</strong> dilatation of extrahepatic bile duct within duodenal wall (<a href="/articles/choledochocoele">choledochocoele</a>)</li>
-</ul><p>Komi classification classifies choledochal cyst into 3 types based on the anomalous union of the pancreatic-bile duct (AUPBD) <sup>2</sup>.</p><h4>Radiographic features</h4><p>Imaging of the biliary tree can be achieved with ultrasound, CT, direct contrast studies (ERCP, PTC) or MRI. </p><h5>Ultrasound</h5><p>Key to the diagnosis is a dilated cystic lesion which communicates with the bile duct and is separate from the gall bladder. Careful search for other causes needs to also be undertaken (see differential below), remaining cognisant that both stone formation and malignancy are associated with choledochal cysts. </p><h5>CT and MRCP</h5><p>Findings are similar to US, with a greater ability to demonstrate intrahepatic disease. It is important to remember that with CT IVC the contrast mixing in the cyst may be inhomogeneous. It does however have the advantage that it conclusively demonstrates communication with the biliary tree <sup>1</sup>.</p><h4>Complications</h4><p>The two most frequent complications of choledochal cysts are stone formation and malignancy. Complications include:</p><ul>- +</ul><p>The Todani classification scheme has been called into question in surgical literature, with claims that it may unfairly link multiple distinct processes into a spuriously coherent grading scheme <sup>7,8</sup>.</p><p>The Komi classification classifies choledochal cyst into 3 types based on the anomalous union of the pancreatic-bile duct (AUPBD) <sup>2</sup>.</p><h4>Radiographic features</h4><p>Imaging of the biliary tree can be achieved with ultrasound, CT, direct contrast studies (ERCP, PTC) or MRI. </p><h5>Ultrasound</h5><p>Key to the diagnosis is a dilated cystic lesion which communicates with the bile duct and is separate from the gall bladder. Careful search for other causes needs to also be undertaken (see differential below), remaining cognisant that both stone formation and malignancy are associated with choledochal cysts. </p><h5>CT and MRCP</h5><p>Findings are similar to US, with a greater ability to demonstrate intrahepatic disease. It is important to remember that with CT IVC the contrast mixing in the cyst may be inhomogeneous. It does however have the advantage that it conclusively demonstrates communication with the biliary tree <sup>1</sup>.</p><h4>Complications</h4><p>The two most frequent complications of choledochal cysts are stone formation and malignancy. Complications include:</p><ul>
References changed:
- 7. Visser B, Suh I, Way L, Kang S. Congenital Choledochal Cysts in Adults. Arch Surg. 2004;139(8):855-60; discussion 860-2. <a href="https://doi.org/10.1001/archsurg.139.8.855">doi:10.1001/archsurg.139.8.855</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/15302695">Pubmed</a>
- 8. Martin R. Biliary Cysts: A Review and Simplified Classification Scheme. Surg Clin North Am. 2014;94(2):219-32. <a href="https://doi.org/10.1016/j.suc.2014.01.011">doi:10.1016/j.suc.2014.01.011</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/24679418">Pubmed</a>
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