Hepatic adenoma and focal nodular hyperplasia: a diagnostic dilemma.

Focal Nodular Hyperplasia (FNH) and Hepatic Adenoma (HA) remain difficult diagnostic problems due to their variable imaging appearances. Five new cases are presented, illustrating this variability, and the current literature is reviewed. Ultrasonography is a sensitive modality for their detection but is otherwise non-specific. On computer tomography, the presence of a scar suggests FNH, whilst haemorrhage suggests HA. However these features are seen in only a small number of cases. Radionuclide (colloid) scanning aids considerably in FNH but a definitive role has not been found in HA. Angiography is helpful, providing anatomical information, sometimes diagnostic (septated blush in FNH, hypovascular areas in HA) and able to discern benign from malignant lesions. Where imaging is not definitively diagnostic, percutaneous biopsy is indicated if FNH is suspected and surgical biopsy if HA is felt likely.