How is focal nodular hyperplasia (FNH) typically managed?

Management of Focal Nodular Hyperplasia (FNH)

Focal nodular hyperplasia (FNH) requires no routine monitoring or intervention regardless of size, as it has no malignant potential and rarely causes complications. 1

Epidemiology and Diagnosis

• FNH is the second most common benign liver lesion after hemangioma, with a prevalence of 0.3% to 3% 2, 1
• More common in females than males (26:1 ratio) 1
• May coexist with other vascular hepatic lesions such as hemangiomas in up to 20% of cases 2, 1
• Diagnosis typically made through imaging:
  • MRI with liver-specific contrast is highly accurate
  • Characteristic findings include central stellate scar and "spoke-wheel" appearance on contrast-enhanced imaging 1

Management Approach

1. Conservative management is the standard of care 1, 3

   • No routine monitoring required after diagnosis 1
   • No follow-up imaging necessary for asymptomatic FNH 1
   • Conservative treatment is effective in approximately 94.4% of cases 3

2. Special considerations:

   • Pregnancy: No monitoring required during pregnancy, regardless of FNH size 2, 1
   • Unlike hepatocellular adenomas, which require monitoring during pregnancy if >5cm, FNH poses minimal risk 2, 1
   • Vaginal delivery is not associated with increased risks 1

3. Surgical intervention is rarely indicated and should be considered only in specific circumstances:

   • Persistent symptoms clearly attributable to FNH (e.g., pain) 1, 4
   • Unusual behavior such as rapid growth 4
   • Risk of rupture (extremely rare) 5

Surgical Options When Indicated

When surgery is necessary (which is rare):

• Laparoscopic resection is preferred 1, 5
• Preoperative transcatheter arterial embolization (TAE) may facilitate safer surgical resection for large hypervascular tumors 1, 5, 6
• TAE represents a promising alternative to surgery for cases requiring intervention 6

Clinical Pearls and Pitfalls

• Common pitfall: Unnecessary surgery for asymptomatic FNH. Studies show a historically high incidence of surgery despite no recommendation for treatment 3, 6
• Important distinction: Unlike hepatocellular adenomas, which may require intervention if >5cm, FNH generally requires no intervention regardless of size 2, 1
• Diagnostic challenge: Ensuring accurate diagnosis is critical, as misdiagnosis may lead to unnecessary interventions. The differential diagnosis includes hepatocellular adenoma, hepatocellular carcinoma, and hypervascular metastasis 7
• Follow-up strategy: Patients with confirmed FNH should be reassured about its benign nature and lack of need for routine follow-up 1, 3

The management of FNH should follow a similar approach to that of hemangiomas, with observation being appropriate for the vast majority of cases 4.