Breast Cancer Suspicion in a Transgender Male-to-FemalePatient on Hormone Replacement Therapy Presenting withRight Breast Mass: Breast Cancer Risk Assessment andPresentation of a Rare Lesion

There has been an increasing use of hormonal therapy among male-to-female (MtF) transgender individuals. This long-termhormone replacement therapy (HRT) renders MtF individuals a unique patient subgroup in terms of breast cancer risk. Thiscase describes a MtF transgender who presented with a breast lesion concerning for malignancy following hormonal replacementtherapy. The patient additionally had a strong family history of breast cancer. Final pathology revealed lobular hyperplasia inthe setting of gynecomastia and pseudoangiomatous stromal hyperplasia (PASH). Both pathology findings are rare in biologicalfemales, let alone in the setting of hormone replacement therapy in a MtF individual. While the number of reported cases ofsuspicious breast lesions in this population remains scarce, it presents both a diagnostic and therapeutic challenge due to the natureof the treatment course and the lack of research in this recently growing subgroup of patients.