SUN-040 Hormone Replacement Therapy in Transgender Unmasks Testicular Tumor

Introduction In transwomen, hormonal replacement therapy typically usually consists of anti-androgen and/or estrogens. Per Endocrine Society 2017 guidelines, patients should be evaluated every 3 months in the first year for appropriate signs of feminization and adverse reactions. This includes measuring serum testosterone every 3 months initially and the testosterone level should be < 50 ng/dL. We describe a case of a transwoman patient diagnosed with testicular seminoma during surveillance of hormonal replacement therapy (HRT). Case presentation A 31-year-old male-to-female transgender presents to the endocrine clinic for HRT. She previously had seen another provider for HRT and was started on estradiol valerate 5 mg weekly and leuprolide 3.75 mg every month. After 5 months of therapy, she reported that her testosterone level remained elevated, so spironolactone 100 mg BID was subsequently added. Despite adherence, she was dismayed at how little physical changes she achieved after 1.5 years of HRT. She denies taking exogenous substances or OTC mediation containing androgens. Her examination reveals a male habitus and musculature with male voice, male diamond pubic hair pattern, adult penis size and scrotum measuring 20 cc’s bilaterally. Initial labs revealed total testosterone 131 ng/dl, free testosterone 30.8 ng/dl, bioavailable testosterone 64.6 ng/dl, SHBG 12 nmol/L, LH < 0.07 IU/L, FSH < 0.1 IU/L, and estradiol 146 pg/ml. Due to non-suppressed testosterone level despite undetectable gonadotropins, adrenal androgen labs were obtained which was normal. However, her HCG-beta tumor marker was elevated, 12 IU/L (0-3). This prompted a scrotal ultrasound which revealed 3.2 cm right testis mass. Follow-up PET/CT revealed increased activity localized to the right testis without findings of metastasis. Patient underwent right orchiectomy with pathology revealing seminoma stage 1A pT1bMx. At 2 months postop, her total testosterone is now 8 ng/dl, and she reports that her breast tissue has increased and skin softened. Conclusion Hyperandrogenism can be easily diagnosed in females given more obvious clinical features; however, except for precocious puberty, there are typically no obvious features of exogenous testosterone production in males. Thus, typically no workup is undertaken in males to look for underlying cause, including testicular cancer. While presence of scrotal mass is the most common initial presentation, patients can be asymptomatic until tumor burden is high and there is metastasis. Transwomen should be monitored by obtaining estradiol and testosterone levels following the Endocrine Society guidelines. If patient is on GnRH agonist, her testosterone level should be almost completely suppressed (T <50). A testosterone level > 50 ng/dL while on GnRH therapy should warrant workup for exogenous sources, including testicular cancer and adrenal abnormalities.