What is the recommended management approach for patients with focal nodular hyperplasia (FNH)?

Management of Focal Nodular Hyperplasia (FNH)

Conservative management is recommended for patients with focal nodular hyperplasia (FNH), with surgery reserved only for specific cases with symptoms or rapid growth. 1, 2

Characteristics and Epidemiology

• FNH is the second most common benign liver tumor after hemangioma, with a prevalence of 0.3% to 3% in the general population 1
• It occurs predominantly in reproductive-aged women, with a female-to-male ratio estimated at 26:1 1
• FNH is characterized by focal hyperplasia within normal liver tissue and may be influenced by steroid hormones, though the relationship with estrogen exposure remains controversial 3

Diagnostic Approach

• Diagnosis can be established through non-invasive imaging techniques:
  • Contrast-enhanced ultrasound (CEUS) typically shows strong hyperperfusion from a large feeding artery in the arterial phase, creating a characteristic spoke-wheel appearance 3
  • MRI with liver-specific contrast agents provides high diagnostic accuracy, especially for lesions larger than 3.5 cm 4
  • Typical findings include a central scar and homogeneous enhancement pattern 4
• Liver biopsy should be avoided as it is not necessary for diagnosis and carries a risk of bleeding 3

Management Recommendations

• Conservative management is the standard approach for asymptomatic FNH 2, 1
• Surgical intervention is indicated only in specific circumstances:
  • Persistent symptomatic pain without other identifiable causes 5, 6
  • Rapid growth during follow-up 2, 5
  • Large lesions (>5 cm) that pose a risk of complications 7, 6
• Unlike hepatic adenomas, FNH has an extremely low risk of spontaneous rupture, with only rare cases reported in the literature 1, 7

Special Considerations for Pregnancy

• Pregnancy is not contraindicated in women with FNH 3, 1
• Vaginal delivery is not associated with increased risks 3, 1
• Routine imaging surveillance is not recommended during pregnancy 3
• In a study of 20 pregnant women with FNH, size remained constant or decreased in most patients, with no FNH-related complications 3

Potential Pitfalls

• FNH may be mistaken for hepatocellular carcinoma on imaging, particularly when the liver appears nodular 3
• FNH can coexist with other vascular hepatic lesions such as hemangiomas in up to 20% of cases 1
• Unlike hepatic adenomas, which require close monitoring during pregnancy, FNH does not require special surveillance 1
• Focal nodular hyperplasia is frequently found in patients with hereditary hemorrhagic telangiectasia (HHT), with a prevalence 100-fold greater than in the general population 3

Follow-up Recommendations

• Long-term follow-up studies show that conservative management is effective in over 94% of cases 2
• Initially asymptomatic patients typically remain symptom-free during follow-up 2
• Periodic imaging may be considered for larger lesions, but there is no strong evidence supporting routine surveillance 1, 2