Focal nodular hyperplasia (FNH) is a benign lesion caused by hyperplastic response of hepatocytes in the presence of an abnormal blood vessel. The contraceptive pill acts on growth but does not affect the formation.

FNH is a hamartoma, may be multiple, and is found more in the right lobe below the Glisson’s capsule. There is a central fibrous scar in the larger forms (> 5 cm). Typical appearances is the proliferation of the bile ducts malformed that communicate poorly or do not communicate at all with the biliary system of the adjacent parenchyma.

Case courtesy: Dr.ssa Barbara Severini and Dr Fabio Denicolò.