Focal nodular hyperplasia

Clinical features

  • < 2% of childhood liver tumours
  • 4-10% of benign childhood tumours
  • Unusual in the first year of life
  • 7-15% occur in children
  • Association with hepatic cavernous haemangioma (20%), glycogen storage disease type Ia, portal hypertension, hemi hypertrophy, brain tumours and congenital cardiovascular anomalies
  • X-ray shows mass with a central scar
  • Angiography shows centrifugal hypervascularity
  • Left lobe 60%, right lobe 30% and bilateral 10%

 

Cytopathology

  • Smears  represent normal liver constituents:
    • Sheets of benign hepatocytes
    • Bile duct epithelial cells
    • Benign spindle cells rarely seen
    • Reticulin framework decreased in cell block
    •  

Immunocytochemistry

Non-contributory

 

Modern diagnostic techniques

Non-contributory

 

Differential diagnosis

  • Hepatocellular adenoma
    • Rare in children
    • Absence of bile ducts (the presence of bile ducts rules out adenoma)
  • Normal liver parenchyma
    • Impossible to rule out
  • Cirrhotic regenerative nodule
    • Impossible to rule out if the clinical context is appropriate
  • Well-differentiated hepatocellular carcinoma
    • Increased nuclear/cytoplasmic ratio
    • Endothelium-lined epithelial groups
    • Uniform tumour cells
    • Trabecular thickening in cell block
    • Reticulin framework decreased in cell  block
    • Diffuse CD34 reactivity (sinusoidal capillarization)
    • CEA: abnormal canaliculus pattern

 

Main points

  • Excision unnecessary if diagnosis can be trusted
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