RESUMO
Disorders or differences of sexual development encompasses an important group of conditions that affects up to 1 in 5,000 live births. Many individuals living in the female gender includes Turner syndrome, congenital adrenal hyperplasia and conditions with 46XY karyotype such as gonadal dysgenesis (Swyer syndrome). Individuals are commenced on high dose oestrogen to initiate and maintain development of secondary sexual characteristics such as breasts which is paramount in them identifying in the female gender. We highlight the first case of a patient with Swyer syndrome who was treated with long term oestrogen therapy and later developed breast cancer. In individuals with gonadal dysgenesis, testicular malignancy is a recognised risk and is screened for. Prolonged exposure to exogenous and endogenous hormones can increase the risk of breast cancer however how much this risk increases in those taking high dose hormones is not documented in the literature. We aim to highlight the importance of breast cancer treatment and surgical reconstruction in this group and whether they should be considered for early breast cancer screening. CONCLUSION: It is imperative that triple assessment is undertaken in every patient with a breast lump, regardless of gender identification. Clinicians must not delay investigations in this patient group due to a misunderstanding of their condition. Those on long term hormone supplementation should be entered into the breast screening program at an earlier age with Magnetic Resonance Imaging surveillance. Careful consideration of post treatment endocrine therapy is required and under the care of the multi-disciplinary team.