Adenoma or atypical hepatic focal nodular hyperplasia: role of preoperative imaging and laparoscopic treatment.

Differentiation of focal nodular hyperplasia (FNH) and other hypervascular liver lesions, such as hepatocellular adenoma (HCA), is important because of the drastically different therapeutic approach. However, FNH can be well distinguished only if it shows a typical aspect; alternatively, in the case of atypical FNH, imaging findings are not specific enough to provide a secure diagnosis and histologic verification of the lesion is required. In addition, HCA cannot be identified conclusively by any current available imaging technique and it can be at best suspected strongly, and this suspicion may lead to liver resection. Herein we report a case of a patient with an unusual FNH nodule presenting at ultrasonographic scanning as an isoechoic mass arising from hepatic segment 4b; the diagnostic indecision between FNH and HCA was not definitively solved even after computed tomography scan and magnetic resonance imaging and the patient was scheduled for a laparoscopic resection. The pathologic examination diagnosed an atypical FNH nodule. The clinical doubt between FNH and HCA remains a problem affecting the clinicians, and more effort should be made in the direction of a better preoperative differentiation of such different conditions. Surgical resection should not be considered as the failure of the preoperative diagnostic attempt, but as the mainstay for a definitive and sure diagnosis.