Nowadays incidental focal hepatic lesions are detected rather frequently by abdominal imaging. A 12 cm diameter liver mass was incidentally found in an abdominal ultrasound in a 26 years old man. Despite an extensive diagnostic workup, the diagnosis of hepatocellular carcinoma could only be attained through the histological study of the surgical specimen. Differential diagnosis of a focal hepatic lesion is reviewed. Radiological assessment and biopsy procedures should follow a protocol. Where doubt exists about the presence of malignancy after fulfilling the diagnostic protocol we believe that it is justified to remove the lesion. This policy allowed to treat successfully our patient. Hepatocellular carcinoma in noncirrhotic occurs much less frequently than in cirrhotic liver, and moreover, it is specially rare to find at such a young age a non fibrolamellar hepatocarcinoma non associated with cirrhosis or a chronic viral infection. Diagnosis, treatment and prognosis of hepatocellular carcinoma are reviewed.