Objective: The relationship between sex hormones and hepatocellular adenoma development is well established. On the contrary, their contribution to liver adenomatosis (LA) development is still a debatable issue. Recently, inactivating mutations of hepatocyte nuclear factor-1α (HNF-1α) transcription factor gene or activating mutations of β-catenin have been demonstrated in some liver adenomas, and a possible link between HNF-1α gene mutations and oral contraceptives has been suggested. Only two cases of regressive LA after hormone withdrawal therapy have been described so far but without any information concerning the molecular characteristics of the tumours. Case: We report the case of a 48-year-old woman with LA, who had been taking an androgenic progestin therapy (lynestrenol) for 10 years. A major regression in the number and size of the lesions was observed 6 months after complete withdrawal of this therapy. Methods: Hepatocellular adenomas were studied by immunohistochemistry for oestrogen, progesterone and androgen receptors (ER, PR and AR respectively), and for β-catenin. Direct sequencing of the HNF-1α gene was also performed. Results: For the first time, we demonstrate significant immunostaining of AR in the hepatocellular adenomas. This staining was negative in the partially regressive adenoma. Immunostainings for ER and PR were negative. HNF-1α and the β-catenin pathways were not involved in tumour pathogenesis. Conclusions: Our case suggests a role of androgenic progestin therapy in some cases of LA. Hormone therapy withdrawal may induce a significant regression in lesions.