Focal nodular hyperplasia

It is a benign lesion, presenting as a solitary nodule or, less commonly, as several nodules. Most patients are women in their third or fourth decade. The lesions usually have a central scar and are composed of nodules of hepatocytes, which are separated from one another by radiating fibrous septae containing bile ductules.

Cytologic diagnostic features

• Hepatocytes without significant atypia
• Bile ductular cells

Differential diagnosis

• Hepatic adenoma
• Regenerating nodules in cirrhosis
• Normal liver

These lesions are not cytologically distinguishable.