Meningiomas are the most common tumors of the central nervous system. Most meningiomas are benign and occur mainly in middle aged women. Risk factors include female sex, exposure to ionizing radiation, and age. The relationship between meningiomas and sex hormones is supported by their higher expression of specific receptors. Only few cases of meningiomas in identical twins have been reported. Cyproterone acetate (CPA) is an antiandrogenic progestin used to treat hirsutism in some countries. We report the case of identical twin sisters with multiple CPA-induced meningiomas and their spontaneous decrease after drug discontinuation, permitting surgical abstention.

This study is an original case report with 18 month follow up, at University Hospital Reims, France. Study population are two 48-year-old identical twin sisters under CPA treatment against hirsutism with 50mg daily during 30 years (total dose of approximately 547.5g per person).

We described four biggest lesions (two per patient) as markers of evolution with the average decrease of volume of the four described lesions (combined results patient one and two) after eighteen month of CPA stopping was 58.6 %.

These two identical twin patients illustrate the risk of development of multiple meningiomas with long-term use of CPA. Eighteen-month follow-up showed decrease of meningiomas after treatment interruption. The history of these two patients suggests the presence of genetic abnormalities that would favor the development of progestin-associated meningiomas. In our case influence of both factors seems strongly possible. The stopping of CPA permitted surgical abstention and significant reduction of tumor volume.