Abstract
BACKGROUND: Focal nodular hyperplasia (FNH)-like lesions are hyperplastic formations in patients with micronodular cirrhosis and a history of alcohol abuse. Although pathologically similar to hepatocellular carcinoma (HCC) lesions, they are benign. As such, it is important to develop methods to distinguish between FNH-like lesions and HCC. AIM: To evaluate diagnostically differential radiological findings between FNH-like lesions and HCC. METHODS: We studied pathologically confirmed FNH-like lesions in 13 patients with alcoholic cirrhosis [10 men and 3 women; mean age: 54.5 ± 12.5 (33-72) years] who were negative for hepatitis-B surface antigen and hepatitis-C virus antibody and underwent dynamic computed tomography (CT) and magnetic resonance imaging (MRI), including superparamagnetic iron oxide (SPIO) and/or gadoxetic acid-enhanced MRI. Seven patients also underwent angiography-assisted CT. RESULTS: The evaluated lesion features included arterial enhancement pattern, washout appearance (low density compared with that of surrounding liver parenchyma), signal intensity on T1-weighted image (T1WI) and T2-weighted image (T2WI), central scar presence, chemical shift on in- and out-of-phase images, and uptake pattern on gadoxetic acid-enhanced MRI hepatobiliary phase and SPIO-enhanced MRI. Eleven patients had multiple small lesions (< 1.5 cm). Radiological features of FNH-like lesions included hypervascularity despite small lesions, lack of "corona-like" enhancement in the late phase on CT during hepatic angiography (CTHA), high-intensity on T1WI, slightly high- or iso-intensity on T2WI, no signal decrease in out-of-phase images, and complete SPIO uptake or incomplete/partial uptake of gadoxetic acid. Pathologically, similar to HCC, FNH-like lesions showed many unpaired arteries and sinusoidal capillarization. CONCLUSION: Overall, the present study showed that FNH-like lesions have unique radiological findings useful for differential diagnosis. Specifically, SPIO- and/or gadoxetic acid-enhanced MRI and CTHA features might facilitate differential diagnosis of FNH-like lesions and HCC.