Galactorrhea and Pituitary Microadenoma in an 18-Year-Old Transfeminine Youth: A Case Report

Gender-affirming hormone therapy (GAHT) improves psychological well-being in transfeminine individuals but may cause endocrine alterations, including hyperprolactinemia and, rarely, pituitary adenomas. We report the youngest known case of galactorrhea and pituitary microadenoma associated with unsupervised GAHT, highlighting multifactorial contributing factors.

An 18-year-old transfeminine youth presented with galactorrhea while taking self-administered GAHT without medical supervision. Laboratory testing showed elevated prolactin, and magnetic resonance imaging revealed a pituitary microadenoma. Contributing factors included high-dose estradiol, cyproterone acetate, concomitant antiretroviral and antidepressant therapy, and frequent breast massage.

This case highlights the endocrine vulnerability of adolescents using unsupervised GAHT. The combined effects of estrogen excess, antiandrogen therapy, serotonergic and dopaminergic modulation, and mechanical breast stimulation likely contributed to hyperprolactinemia. Limited pediatric data and lack of structured hormonal monitoring delayed diagnosis and optimal management. Multidisciplinary care integrating endocrine follow-up and mental health support is essential to ensure treatment safety.

Unsupervised GAHT in adolescents can lead to significant endocrine complications through multifactorial mechanisms. Early recognition, structured monitoring, and coordinated multidisciplinary care are crucial to balance gender-affirming goals with patient safety.