Breast cancer in a transgender woman undergoing gender-affirming exogenous hormone therapy.

Gender-affirming hormone therapy may be utilized by transgender women hoping to induce feminizing changes and suppress the effects of endogenous testosterone. It is well established that exogenous hormone use increases risk of breast cancer in cisgender women; however, a link in the transgender population is less clear. Our case presents a transgender woman undergoing gender-affirming exogenous hormone therapy who subsequently developed breast cancer. We review the available literature regarding risks of exogenous hormone therapy with regards to breast cancer development. Additionally, we present current societal guidelines and recommendations for screening in this population.