Focal nodular hyperplasia of the liver. Five cases.

Focal nodular hyperplasia (FNH) of the liver is a benign tumour with a cirrhosis-like appearance. The tumour is rare, but it is a relevant differential diagnosis in young patients with a hepatic mass. Radiologically and grossly FNH cannot be distinguished from malignant tumours. Biopsy with frozen section usually provides the diagnosis. There is no evidence that FNH is premalignant. Only a few patients have symptoms requiring treatment (pain, loss of appetite, nausea, and vomiting) and complications (weight loss, portal compression) are extremely rare. The preferred treatment for symptomatic tumours is removal. In patients without symptoms FNH can be left untreated without any undue risk.