RESUMEN
BACKGROUND: Medical affirmation, including gender-affirming hormones, is an essential component in the treatment of many transgender and gender-diverse youth. The risk of venous thromboembolism (VTE) during testosterone therapy for gender-affirming care is not fully elucidated. OBSERVATION: The case describes a 17-year-old transgender male treated with testosterone therapy who presented with an occlusive deep vein thrombosis of right axillary and subclavian veins. Testosterone level was 920 ng/dL at the time of the deep vein thrombosis, and he had no risk factors for VTE. A complete hypercoagulable workup was negative. CONCLUSIONS: The possibility of testosterone therapy as a risk factor for VTE may suggest the need to include this information during informed consent discussions. Long-term anticoagulation may be considered for those restarting testosterone therapy.