What is Von Meyenburg complex?

Von Meyenburg Complex (Biliary Hamartomas)

Von Meyenburg complexes are benign congenital malformations of the bile ducts that typically require no treatment, and patients should be counseled on their benign nature. 1

Definition and Pathophysiology

Von Meyenburg complexes, also referred to as biliary hamartomas or bile duct hamartomas, are part of the spectrum of ductal plate malformations that occur during embryonic development. 1, 2 These lesions represent disorganized small intrahepatic bile ducts that failed to properly remodel during fetal development. 3, 4

• Prevalence ranges from 0.35% to 5.6% in the general population, though they are often underdiagnosed due to their asymptomatic nature. 3
• They occur predominantly in adults with no clear sex predilection, though some series show slight female predominance. 3, 5
• The lesions may occur in an otherwise normal liver or in association with other ductal plate abnormalities including Caroli disease, congenital hepatic fibrosis, and polycystic liver disease (ADPKD or ADPLD). 1, 6

Clinical Presentation

Multiple bile duct hamartomas are usually detected as incidental findings during imaging or pathological examination. 1 The vast majority of patients are asymptomatic.

• Biliary hamartomas do not affect liver function in most cases. 1
• When symptomatic, patients may present with mild, non-specific abdominal pain and discomfort. 5
• Rare presentations can mimic infectious processes such as cholangitis or liver abscesses. 5
• The lesions are typically small (<1 cm to 1.5 cm), multiple, and scattered throughout the liver parenchyma. 2, 5

Imaging Characteristics

Von Meyenburg complexes present a diagnostic challenge because they may be confused with miliary liver metastases on imaging studies. 1

• On imaging, they typically appear as tiny (<1 cm) hypodense lesions scattered throughout the liver. 2
• MRI shows distinct characteristics with hyperintense cystic nodules on T2-weighted images that do not communicate with the biliary tree. 5, 7
• The lesions show variable contrast enhancement patterns, which can be inconsistent and contribute to diagnostic uncertainty. 7
• Biopsy is often necessary for definitive diagnosis, particularly when liver metastases are suspected in patients with known primary malignancies. 1, 3, 7

Malignant Transformation Risk

The relationship between Von Meyenburg complexes and malignancy remains controversial but appears to carry a very low absolute risk.

• Malignant transformations to hepatocellular or cholangiocarcinoma have been described in incidental case reports. 1
• The incidence of malignancies associated with biliary hamartomas is unclear, but the relatively low number of case reports relative to the 5.6% prevalence suggests a very low risk. 1
• However, biliary hamartomas were found in up to 40% of resected liver specimens of intrahepatic cholangiocarcinomas, suggesting possible malignant transformation through genetic mutations rather than mere coincidence. 1
• The time span from benign biliary hamartomas to development of detectable malignant lesions is unknown, though case reports suggest progression over many years. 1

Management Recommendations

Patients should be counseled on the benign nature of biliary hamartomas (strong recommendation, 100% consensus from EASL). 1

• No specific treatment is required for asymptomatic Von Meyenburg complexes. 1
• There is insufficient data to make recommendations regarding surveillance for malignancy in asymptomatic patients with isolated biliary hamartomas. 1
• Asymptomatic patients with biliary hamartomas and concomitant liver diseases should have follow-up determined by the primary liver disease, not by the hamartomas themselves. 1
• The presence of Von Meyenburg complexes does not rule out other synchronous neoplasms, so appropriate evaluation for suspected malignancy should proceed when clinically indicated. 3

Key Clinical Pitfalls

• Do not mistake Von Meyenburg complexes for metastatic disease based solely on imaging appearance; their multifocal nature can easily simulate metastases. 1, 3
• Distinguish Von Meyenburg complexes from other benign biliary lesions including peribiliary glands, reactive ductular proliferation, and bile duct adenomas, particularly in the presence of inflammation. 1
• Avoid unnecessary surveillance imaging in patients with isolated, asymptomatic biliary hamartomas without other liver disease. 1
• When malignancy is suspected in a patient with known Von Meyenburg complexes, biopsy remains the gold standard for definitive diagnosis. 1, 7