How is focal nodular hyperplasia (FNH) typically managed?

Management of Focal Nodular Hyperplasia (FNH)

Focal nodular hyperplasia (FNH) should be managed conservatively without routine monitoring or surveillance after diagnosis, as it has no malignant potential and rarely causes complications. 1

Characteristics and Epidemiology

• FNH is the second most common benign liver tumor after hemangioma
• Prevalence ranges from 0.3% to 3% 1
• More common in females than males (estimated sex ratio of 26:1) 2
• Occurs more frequently in women of reproductive age 3

Diagnostic Approach

• Diagnosis typically made through imaging:

  • MRI with liver-specific contrast offers highest sensitivity (87%) 4
  • CT scanning has moderate sensitivity (70%) 4
  • Ultrasound has lower sensitivity (30%) 4

• Typical imaging features include:

  • Central stellate scar containing a large artery
  • "Spoke-wheel" appearance on contrast-enhanced imaging
  • Strong hyperperfusion from center outward during arterial phase
  • "Lightbulb" sign (lesion filled with contrast and more enhanced than surrounding liver) 2

Management Algorithm

1. Asymptomatic FNH

• Conservative management is recommended 5
• No routine monitoring or follow-up imaging is necessary 1
• No intervention required regardless of size 1

2. Symptomatic FNH

• Most FNH lesions are asymptomatic and discovered incidentally
• For persistent symptoms clearly attributable to FNH (after excluding other causes):
  • Pain is the most common symptom warranting intervention 4
  • Larger tumor size (p=0.006) and multiple lesions (p=0.02) are associated with pain 4
  • Surgical resection may be considered for persistent symptoms 6

3. Special Considerations

Pregnancy

• Pregnancy is not contraindicated in women with FNH 2, 1
• Vaginal delivery is not associated with increased risks 2
• Unlike hepatocellular adenomas, FNH does not require monitoring during pregnancy 1
• Imaging is not routinely recommended to monitor FNH during pregnancy 2

Unusual Behavior

• Surgical intervention may be considered in rare cases of:
  • Rapid growth during follow-up 6
  • Large lesions with risk of rupture (though this is extremely rare) 3

Treatment Options When Indicated

• Laparoscopic resection is preferred when surgery is indicated 3
• For large hypervascular tumors, preoperative transcatheter arterial embolization may facilitate safer surgical resection 3

Important Distinctions from Other Benign Liver Lesions

• Unlike hepatocellular adenomas >5cm, FNH does not require monitoring during pregnancy 1
• Unlike large hemangiomas (>4cm), which have a 3.2% risk of rupture, FNH rarely ruptures 2
• Avoid implementing unnecessary surveillance protocols that are appropriate for other liver lesions but not for FNH 1

Long-term Outcomes

• Conservative management is effective in approximately 94.4% of cases 5
• Surgical intervention is rarely needed (5.5% of cases) 5
• Even initially symptomatic patients often remain stable without worsening of symptoms 5

The benign nature of FNH and its excellent long-term outcomes with conservative management make observation the standard of care for most patients with this condition.