ABPJ & CDC [DT + S]

Todani Classification of Choledochal Cysts

The image provided classifies choledochal cysts into five types, which are associated with various anatomical abnormalities:

• Type I (IA, IB, IC): Cystic dilatation of the common bile duct (CBD) associated with an anomalous pancreaticobiliary duct junction (APBDJ).
• Type II: Diverticulum of the CBD.
• Type III (Choledochocele): Cystic dilatation within the duodenal wall.
• Type IV (IVA, IVB): Multiple cysts, both intrahepatic and extrahepatic.
• Type V (Caroli’s Disease): Cystic dilatation of intrahepatic bile ducts.

New Variants of CDC

• Type ID: Dilatation of CBD, common hepatic duct (CHD), and cystic duct.
• Type VI: Isolated cystic duct dilatation.
• Type II: 60% occur in the common hepatic duct (CHD), 20% in the suprapancreatic CBD, and 20% in the intrapancreatic CBD.
• Type IIIA: Ampullary cyst where both CBD and main pancreatic duct (MPD) open into the cyst, which then opens into the duodenum.
• Type IIIB: Diverticulum of intra-duodenal CBD with normal CBD opening into the duodenum.

Specific Variants

• Type V (Caroli’s Disease): Associated with congenital hepatic fibrosis (CHF) ⇒ Grumbach’s Disease ⇒ autosomal recessive inheritance.
• Forme Fruste: APBDJ without CDC, with the same risk of malignancy as CDC.

Clinical Presentation of CDC

Answer: d) Pediatric age group present with pancreatobiliary complications

Explanation: Pediatric patients usually do not present with pancreatobiliary complications. These are more common in adults.

• 25% of CDC cases present in infancy.
• Up to 55% present before 10 years of age.
• 25% present in adulthood.
• Adults are more likely to present with pancreatobiliary complications.

Proposed Mechanisms for Development of CDC

Answer: e) None of the above

Explanation: All the options listed are proposed mechanisms in the development of CDC.

CDC Presentation and Risk of Malignancy

Answer: d) 50% present with pancreatitis

Explanation: Only about 30% of patients present with pancreatitis, not 50%.

• 30% of patients with CDC present with pancreatitis due to protein plug and bile reflux.
• Cystolithiasis is most common in adults.
• Hepatobiliary malignancies associated with CDC include cholangiocarcinoma, adenocarcinoma, squamous cell carcinoma, anaplastic carcinoma, bile duct sarcoma, hepatocellular carcinoma, pancreatic carcinoma, and gallbladder carcinoma.
• Incidence of carcinoma has been estimated at 12% in patients with choledochoceles (Type III CDC), particularly when biliary epithelium is present.
• However, choledochal cysts are associated with a high rate of BilIN (28.5%).

Congenital Biliary Cystic Disease and Intrahepatic Cholangiocarcinoma (IHCC)

Risk of Cholangiocarcinoma

• Untreated Choledochal Cysts and Caroli Disease:
  • Increased Risk: Both conditions carry a significant risk of developing cholangiocarcinoma.
  • Incidence: The risk is estimated to be between 10% and 20% if the cyst is not resected by the age of 20 years.
• Post-Cyst Resection:
  • Reduced Risk: Patients who have had their cysts resected show a very low incidence of cholangiocarcinoma.
  • Subsequent Development: Despite resection, there are recorded cases of cholangiocarcinoma developing post-cyst excision.

Mechanism of Malignant Transformation

• Unclear Mechanism: The exact process of malignant transformation in these patients is not fully understood.
• Potential Contributing Factors:
  • Abnormally High Union of Pancreatic and Bile Ducts: Many patients with choledochal cysts have this anomaly.
  • Biliary Stasis and Chronic Reflux: Chronic reflux of pancreatic secretions may lead to prolonged inflammation of the biliary epithelium, contributing to malignancy.

Pancreaticobiliary Maljunction (PBM)

• Risk Factor: In patients with PBM alone, there is a 7% risk of developing cholangiocarcinoma.

Malignancy Risk Reduction After Choledochal Cyst Excision

Key Points:

• Reduction in Malignancy Risk is based on three key presumptions:
  1. Pancreatic Secretions Elimination: The potential carcinogenic effect of pancreatic secretions is eliminated because of total diversion from the biliary tract.
  2. Reduced Mutagenic Bile Acids: The production of mutagenic secondary bile acids is reduced because bacterial overgrowth in the bile is less frequent.
  3. Excision of Abnormal Epithelium: The abnormal cyst epithelium, which might have a predisposition to malignant transformation, is excised.
• Clinical Outcomes:
  • The clinical results of cyst excision and Roux-en-Y hepaticojejunostomy have been excellent.
  • Most reports with late follow-up confirm that the majority of patients remain asymptomatic after excision.
• Complications:
  • The rate of anastomotic stricture following hepaticojejunostomy ranges from 1.5% to 13%.

MCQ:

Answer: d) 100% risk reduced after excision

Explanation: While the risk of malignancy is significantly reduced after the excision of a choledochal cyst, it is not completely eliminated. There is still a residual risk of developing malignancy even after surgical intervention, hence the statement that the risk is 100% reduced is incorrect.

Surgical Management Based on Todani Classification

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Choledochal Cyst [Speed]

Dilated CBD on Imaging

How to differentiate the cause of CBD dilatation via imaging and clinical scenarios?

• Differential diagnosis:
  • CBD Obstruction = Continuous Upstream Dilatation seen
    • CBD Stone
      • Filling defects seen
    • CBD Stricture / stenosis
  • Choledochal Cyst
    • Only Dilated CBD seen
    • IHBR will be normal
    • BUT IN TYPE 4a Cyst = IHBRD present but Peripheral will be collapsed

Choledochal Cysts

Overview

• Definition: Choledochal cysts are a rare congenital anomaly characterized by the dilatation of the extrahepatic bile ducts, with possible associated intrahepatic duct dilatation.
• Typical Presentation:
  • Usually presents before 10 years of age.
  • Classic Triad of symptoms:
    • Palpable mass
    • Abdominal pain
    • Jaundice
• Associated Risks:
  • Chronic inflammation.
  • Increased risk for cholangiocarcinoma.

Classification of Choledochal Cysts

• Type I: Fusiform extrahepatic duct dilatation.
• Type II: Extrahepatic duct diverticulum.
• Type III: Choledochocele from a dilated terminal CBD.
• Type IV: Multifocal dilatation involving both intrahepatic and extrahepatic ducts.
• Type V: Cystic dilatation of the intrahepatic bile ducts, synonymous with Caroli disease.

Caroli Disease

• Association: Part of hepatic fibropolycystic diseases.
• Manifestation: Hepatic involvement in autosomal recessive polycystic kidney disease (ARPKD).
• Imaging Considerations:
  • Important to demonstrate the connection with the bile ducts to differentiate from multiple cysts or biliary hamartomas.
  • Central dot sign on CT or MRI, indicating central enhancing portal venous branch within the saccule.

Imaging and Diagnosis

• MRI:
  • Well-suited for diagnosing and classifying choledochal cysts.
  • 3D MR cholangiograms can depict both normal and abnormal anatomy.
  • Direct coronal imaging and delayed scans post hepatocyte-specific gadolinium-based contrast agents aid in further evaluation.

Contemporary Nomenclature

• Subtypes: Types I and IV have been further subdivided.
• Current Trends: Some advocate for replacing the numeric classification system with a more descriptive and clinically meaningful nomenclature.

Todani ; Alonso Lej classification of Choledochal cysts

Type I Cysts

• Definition: Solitary fusiform or saccular dilations of the CBD and CHD.
• Prevalence: Most common bile duct cyst (50% to 90%).
• Subtypes:
  • Type IA: Gall bladder arises from CDC
    • Most common subtype.
    • Associated with APBJ. ( ⇒ there is a long common channel which causes reflux)
    • Involves cystic dilation of CBD and CHD.
  • Type IB: Isolated Dilatation of most distal aspect of CBD
    • Focal, segmental dilation of the extrahepatic bile duct.
    • Not associated with APBJ.
  • Type IC:
    • Smooth, fusiform, diffuse, or cylindrical dilation of the extrahepatic ducts.
    • Associated with APBJ. ( ⇒ there is a long common channel which causes reflux)
  • Type ID:
    • Recently proposed.
    • Dilation of cystic duct, CBD, and CHD.
    • Bicornal configuration.
    • Association with APBJ undefined.

Type II Cysts

• Prevalence: 2% to 3%.
• Definition: Discrete, true diverticulum of the extrahepatic bile duct system.
• Location: Often project off the right lateral side of the bile duct.
• Distribution:
  • 60% between CHD and biliary bifurcation.
  • 20% from the suprapancreatic CBD.
  • 20% from the intrapancreatic portion of the CBD.

Type III Cysts

• Prevalence: 1% to 6%.
• Definition: Cystic dilation of the intraduodenal portion of the distal CBD.
• Also Known As: Choledochoceles.
• Lined By: Duodenal or biliary epithelium.
• Management: Primarily endoscopic therapy.
• Subtypes:
  • Type A:
    • Cystic dilations of a segment of the intramural bile duct.
    • Bile duct and pancreatic duct enter the cyst.
  • Type B:
    • Diverticula of the intraampullary common channel.
    • Bile duct opens normally into the duodenum.

Type IV Cysts

• Prevalence: Second most common (15% to 35%).
• Definition: Multiple cysts.
• Subtypes:
  • Type IVa: ( MC subtype)
    • Multiple cysts in both intrahepatic and extrahepatic bile ducts.
    • Predominantly affects the left lobe.
  • Type IVb:
    • Multiple dilations of the extrahepatic biliary tree.
    • Uninvolved intrahepatic biliary tree.
    • Described as "string-of-beads" configuration.

Type V Cysts ( upto 20%)

• Definition: One or more saccular or fusiform dilations of medium- and large-sized intrahepatic ducts.
• Also Known As: Caroli disease.
• Associated Conditions:
  • Caroli syndrome: Intrahepatic ductal ectasia and periportal fibrosis.
  • Autosomal recessive inheritance pattern.
  • Associated with autosomal recessive polycystic kidney disease.

Type VI Cysts

• Definition: Isolated dilation of the cystic duct.
• Prevalence: Very rare.

Forme Fruste Bile Duct Cyst

• Definition: Normal biliary ductal system associated with APBJ.
• Symptoms: Abdominal pain and obstructive jaundice.
• Complications: Predisposition to recurrent pancreatitis.

Management of Choledochal Cysts (CDC)

Type 1 & Type 4 CDC

• Indication: Requires surgical intervention.

Type 1

• Procedure:
  • Excise the dilated portion of the CBD.
  • Perform Roux-en-Y Hepaticojejunostomy (RYHJ).

Type 4

• Type 4a Cysts:
  • Both sides intrahepatic dilated:
    • Excise extrahepatic duct and perform wide anastomosis RYHJ.
    • Liver transplant if necessary.
  • One side of liver intrahepatic involved:
    • Ipsilateral hepatectomy plus RYHJ.
• Type 4b Cysts:
  • Excise the extrahepatic duct.
  • Perform RYHJ.

Type V (Caroli’s Disease)

• Unilateral involvement:
  • Liver resection.
• Bilateral involvement:
  • Liver transplant.

Type 2 CDC

• Procedure:
  • Excision of the cyst.

Type 3 CDC

• Procedure:
  • Endoscopic sphincterotomy.

Special Consideration

• Densely Adherent Cyst to Portal Vein:
  • Previous Approach: Lilly’s procedure (Roux-en-Y Cystojejunostomy).

Type III Cyst (Choledochocele) Management Options:

Preoperative Considerations

• Importance: Preoperative delineation of the distal CBD and pancreatic duct anatomy in relation to the choledochocele is critical for directing treatment.
• Diagnostic Modality:
  • ERCP:
    • Remains the standard diagnostic tool with a 97% diagnostic sensitivity.
    • Offers the option for concurrent definitive management.

Risk of Malignancy

• Previous Estimates: The incidence of carcinoma was previously estimated at 2.5%.
• Recent Findings: A recent systematic review reported a 12% incidence of carcinoma in patients with choledochoceles, particularly those lined with biliary epithelium.
• Histologic Risk Factor: The presence of biliary epithelium is a risk factor for malignant transformation.

Treatment Options

• Goals:
  • Maintain normal outflow of biliary and pancreatic ducts.
  • Minimize future risk of malignancy.
• Choice of Treatment: Depends on age, comorbidities, symptoms, cyst subtype, lesion size, and local anatomic relationships.
• Type A Choledochoceles:
  • Location: Proximal to the orifice of the ampulla and continuous with the bile duct.
  • Treatment:
    • Most commonly treated with endoscopic sphincterotomy.
    • Biopsy of the cyst lining should be performed.
    • If biliary epithelium is present, snare resection is recommended.
• Type B Choledochoceles:
  • Location: Distal to the ampullary orifice.
  • Treatment:
    • Endoscopic or surgical resection.

Treatment Algorithm Based on Cyst Size

• Lesions <3 cm:
  • Intestinal Epithelium: Managed with endoscopic sphincterotomy.
  • Biliary Epithelium:
    • Managed with local resection (endoscopic or open).
    • Surveillance versus pancreaticoduodenectomy may be considered.
• Lesions >3 cm:
  • Intestinal Epithelium: Managed with cyst excision.
  • Biliary Epithelium:
    • Managed with cyst excision with surveillance versus pancreaticoduodenectomy.

Long-term Outcomes and Considerations

• Endoscopic Treatment:
  • Favored due to excellent long-term results and diagnostic advantage of ERCP in defining terminal pancreaticobiliary anatomy.
• Surgical Intervention:
  • Reserved for cases with confirmed malignancy or when lesions are not amenable to endoscopic therapy.
• Surveillance:
  • The role of surveillance post-management is not well defined.
  • Consideration for endoscopic re-evaluation at 6 to 12 months has been proposed.

Congenital Choledochal Cysts and Hepatolithiasis (CCs)

Anatomic Features

• Dilation and Strictures:
  • Occur in both the intrahepatic and extrahepatic biliary tract.
  • Commonly seen in Caroli syndrome.

Associated Conditions

• Intrahepatic Stones:
  • Present in 12%–17% of adult patients with CCs.
• High Incidence of Biliary Tract Carcinoma:
  • Ranges from 10.6% to 20.3%.
• Hepatolithiasis Post-Surgery:
  • Occurs in 3.5% to 23.5% of patients after flow-diversion surgery for congenital CCs.
  • Contributing factors may include bile contamination and anastomotic strictures from Roux-en-Y hepaticojejunal anastomosis, though the exact mechanisms are not fully understood.

Type IV-A Cysts

• Commonly Associated with:
  • Cholangitis.
  • Intrahepatic stone formation.
• Postoperative Incidence of Hepatolithiasis:
  • Higher in Type IV-A cysts compared to Type I cysts:
    • 35% in Type IV-A vs. 5% in Type I cysts.
• Challenges in Surgical Management:
  • Complete resection of dilated left and right hepatic ducts is difficult.
  • Residual dilated ducts may lead to bile stasis.
  • Surgical Approach:
    • Creating a wide anastomosis is attempted by extending the incision along the lateral wall of both hepatic ducts through common hepatic duct-plasty.
    • The goal is to obtain a wide hepaticoenterostomy at the hepatic hilum.

Imaging Diagnosis

https://radiopaedia.org/articles/choledochal-cyst