Thanks to ultrasonography, computed tomography, and nuclear magnetic resonance, not only symptomatic but also asymptomatic liver tumours are discovered more frequently than before. Focal nodular hyperplasia (FNH) is one such tumour, most frequently an asymptomatic tumour of the liver, which predominantly appears in women during the generative period, who have taken oral contraceptives for several years. We present a 27-year-old woman, who has never taken either oral contraceptives or other hormones, in whom a left lobe liver tumour was unexpectedly discovered during a routine investigation performed for psychiatric complaints. The tumour, removed by left lateral bisegmentectomy (segments II and Ill), was composed of two tumoural nodes: 70x58x47 mm and 20x20x20 mm, the bigger one of which had a light grey central stellate scar. Histology revealed a focal nodular hyperplasia. The postoperative recovery was uneventful and the patient stayed symptom free for more than three years after surgery.