 Introduction/Background Transgender is an umbrella term for any individual whose gender identity, or internal sense of self related to gender, differs from the sex assigned at birth. A nonbinary individual may have been assigned female or male at birth but does not strictly identify with either sex. A transfeminine person identifies with the female side of the gender spectrum but was assigned male at birth. These individuals may include transgender women, historically referred to as male-to-female transsexuals. A transmasculine person identifies with the male side of the gender spectrum but was assigned female at birth. These individuals may include transgender men, historically referred to as female-to- male individuals, breast cancer screening transgender and gender-nonconforming recommendations are based on the sex assigned at birth, risk factors, and use of exogenous hormones. A detailed discussion of the continuously evolving terminology in the context of caring for a great diversity of transgender people is beyond the scope of this document. As of the writing of this document, the terminology is derived from the University of California San Francisco (UCSF) Center of Excellence for Transgender Health (https://transcare. ucsf.edu/guidelines/terminology). The incidence of breast cancer in the transgender community is largely unknown because of inadequate epidemiological information and a lack of longitudinal studies. Current evidence consists primarily of case reports and several cohort studies, all of which are retrospective. However, a younger age at the time of breast cancer diagnosis has been reported in transgender people [1-5]. The same breast pathology that occurs in cisgender women can be found in transgender women treated with gender- affirming hormone therapy. Mammary development includes the formation of ducts, lobules, and acini, which is histologically identical to cisgender females and should not be referred to as gynecomastia [4,9,10]. There are
Transgender Breast Cancer Screening.  Introduction/Background Transgender is an umbrella term for any individual whose gender identity, or internal sense of self related to gender, differs from the sex assigned at birth. A nonbinary individual may have been assigned female or male at birth but does not strictly identify with either sex. A transfeminine person identifies with the female side of the gender spectrum but was assigned male at birth. These individuals may include transgender women, historically referred to as male-to-female transsexuals. A transmasculine person identifies with the male side of the gender spectrum but was assigned female at birth. These individuals may include transgender men, historically referred to as female-to- male individuals, breast cancer screening transgender and gender-nonconforming recommendations are based on the sex assigned at birth, risk factors, and use of exogenous hormones. A detailed discussion of the continuously evolving terminology in the context of caring for a great diversity of transgender people is beyond the scope of this document. As of the writing of this document, the terminology is derived from the University of California San Francisco (UCSF) Center of Excellence for Transgender Health (https://transcare. ucsf.edu/guidelines/terminology). The incidence of breast cancer in the transgender community is largely unknown because of inadequate epidemiological information and a lack of longitudinal studies. Current evidence consists primarily of case reports and several cohort studies, all of which are retrospective. However, a younger age at the time of breast cancer diagnosis has been reported in transgender people [1-5]. The same breast pathology that occurs in cisgender women can be found in transgender women treated with gender- affirming hormone therapy. Mammary development includes the formation of ducts, lobules, and acini, which is histologically identical to cisgender females and should not be referred to as gynecomastia [4,9,10]. There are