A 27-year-old man, previously healthy, had an enlarging liver mass incidentally noted at a health check-up 6 months earlier. There were no known risk factors for hepatocellular carcinoma. The hepatic tumour seen on magnetic resonance imaging had characteristics of high T2 and low T1 signals, early hyper-enhancement and mild delayed enhancement, which was atypical for focal nodular hyperplasia (FNH). An atypical hepatectomy was performed smoothly and the pathologic confirmation of FNH was finally made. He was discharged without complications.