Focal nodular hyperplasia (FNH) is a benign 'tumor-like' mass of the liver. It has characteristic imaging features on contrasted-enhanced cross-sectional imaging.
FNH is most frequently identified in young to middle-aged adults, with a strong female predilection.
On CT and MRI the imaging features are classical, which are:
- Intense early arterial phase enhancement, with the exception of the central fibrotic scar.
- Isointense to liver on portal venous phase.
- On the delay phase, the central scar enhances in most cases, as contrast is retained.
This lesion can be left well alone with no need for percutaneous biopsy.