A case is reported of a poorly differentiated hepatocellular carcinoma that occurred in a 65-year-old patient who was on hormonotherapy for prostatic adenocarcinoma. The diagnosis of hepatocellular carcinoma was made 3 months after the initiation of a hormonal treatment with cyproterone acetate (for 1 month) and an LH-RH agonist. A cause and effect relationship between steroid hormones and hepatocellular carcinoma has been advocated in the literature. The occurrence of hepatic malignancy after a short hormonal therapy makes our case very unusual.