What are the congenital anomalies of the hepatobiliary (liver and bile duct) system according to Bailey and Love?

Congenital Anomalies of the Hepatobiliary System According to Bailey and Love

The main congenital anomalies of the hepatobiliary system include choledochal cysts, Caroli disease, Caroli syndrome, biliary atresia, biliary hamartomas, and congenital hepatic fibrosis, all of which can significantly impact morbidity and mortality if not properly managed.

Choledochal Cysts

• Choledochal cysts are congenital malformations of the biliary system with prevalence varying from 1:100,000 in Western countries to 1:13,000 in Japan 1
• They are categorized according to the Todani classification based on location, shape, and multiplicity 1
• Type I and IV cysts with sacculation or fusiform dilation of the extrahepatic bile duct are most common and require surgical resection 1
• These cysts are considered premalignant, with a risk of malignant transformation (cholangiocarcinoma) up to 30% 1
• Even after resection, there remains a risk of metachronous malignant lesions (median incidence 5.6%, range 0.7-40%) 1
• Patients with choledochal cysts should be operated on and subsequently undergo surveillance 1

Caroli Disease and Caroli Syndrome

• Caroli disease (type V choledochal cysts in Todani classification) is characterized by cystic dilatation of intrahepatic bile ducts 1
• Caroli syndrome combines bile duct dilatation with congenital hepatic fibrosis 1
• The prevalence of cholangiocarcinoma in both conditions is approximately 7%, significantly higher than the general population 1
• Caroli syndrome is likely part of the phenotypical spectrum of autosomal recessive polycystic kidney disease (ARPKD) 1
• Patients with Caroli syndrome often develop portal hypertension with venous portosystemic shunting and esophageal varices 1
• Liver transplantation should be considered for patients with severe cholangitis or suspected malignant transformation 2

Biliary Atresia

• Biliary atresia is universally fatal if untreated and is the single most common cause of liver disease leading to liver transplantation in children 1
• Diagnosis and hepatoportoenterostomy (Kasai Procedure) by 8-10 weeks of age is optimal for transplant-free survival 1
• Biliary atresia splenic malformation (BASM) syndrome is a variant with less favorable transplant-free survival 1
• Complications include ongoing cholestasis, cholangitis, portal hypertension, poor weight gain, fat-soluble vitamin deficiencies, and rarely hepatocellular carcinoma 1
• Prophylactic antibiotic regimens with trimethoprim/sulfamethoxazole or neomycin reduce recurrent rates of cholangitis and improve survival 1

Alagille Syndrome

• Alagille syndrome is an autosomal dominant, multisystem disorder affecting the liver, heart, eyes, skeleton, kidneys, and vascular systems 1
• It is characterized by paucity of bile ducts (ductopenia) leading to cholestasis 1
• Mutations in jagged 1 (95% of patients) and neurogenic locus notch homolog protein 2 (5% of patients) genes are responsible 1
• Facial features include triangular facies, hypertelorism, and prominent chin 1
• Partial external biliary diversion, partial internal biliary diversion, and ileal exclusion have improved pruritus, xanthoma burden, and quality of life in some patients 1

Biliary Hamartomas (Von Meyenburg Complexes)

• Biliary hamartomas are considered part of the spectrum of ductal plate malformations 1
• They typically appear as tiny (<1 cm) hypodense lesions scattered throughout the liver 1
• Recognition is crucial because they may mimic liver metastases at first sight 1
• Multiple bile duct hamartomas have normal extra- and intrahepatic bile ducts 1

Congenital Hepatic Fibrosis

• Congenital hepatic fibrosis is often associated with Caroli syndrome 1
• It is characterized by portal hypertension with venous portosystemic shunting and development of esophageal varices and splenomegaly 1
• The presence and degree of hepatic fibrosis may be investigated using non-invasive liver stiffness measurements 1
• It is often part of the phenotypical spectrum of autosomal recessive polycystic kidney disease 1

Other Congenital Anomalies

• Fetal hepatic cysts are generally benign with low likelihood of associated anomalies of the hepatobiliary tract 3
• Congenital biliary cysts are associated with a high rate of progression, abnormal liver function after birth, and clinical symptoms 3
• Anatomical variants of the intrahepatic and extrahepatic bile ducts are common (found in 41% of patients) but are not typically pathological 4
• Multiple adenomatosis with involvement of the entire liver, if symptomatic, is an indication for liver transplantation given the potential for malignant change 1

Clinical Management Considerations

• Regular surveillance should be performed in patients with choledochal cysts and Caroli disease/syndrome to detect development of malignancy 1
• Patients with liver flukes should be treated, but specific surveillance programs cannot currently be recommended due to insufficient evidence 1
• Liver transplantation should be considered for Caroli disease/syndrome with severe cholangitis or suspected malignant transformation 2
• Combined or sequential hepatorenal transplantation should be considered in cases of concomitant symptomatic congenital hepatic fibrosis and renal failure 2