The occurrence of meningioma and tamoxifen use might plausibly be connected; hormonal factors have been proven to be involved in the development of meningioma (Hsu et al., 1997; Wahab and Al-Azzawi, 2003; Lee et al., 2006; Korhonen et al., 2010; Cea-Soriano et al., 2012), and approximately 70% of meningiomas show progesterone receptor expression whereas approximately 30% show estrogen receptor expression (Wahab and Al-Azzawi, 2003). This evidence concerns the gene ESR1 and meningioma.