Precocious sexual development in a male toddler caused by unrecognized transdermal exposure to testosterone: case report and review of the literature

Abstract

Abstract Objectives Exogenous exposure to transdermal testosterone is often overlooked as a cause of precocious sexual development in children. Case presentation A 16-month-old male presented for a second opinion consultation before commencing treatment with bicalutamide and anastrozole for a presumptive diagnosis of familial gonadotropin-independent male-limited sexual precocity. Enlargement of the penis was first observed at four months of age. The initial evaluation showed isolated elevation of his plasma testosterone level; however, by 16 months, his testosterone level was prepubertal and no pathogenic variants in the LHC GR gene were identified. The history revealed that his grandfather, who had cared for him regularly in the first year of life, had used testosterone gel for treatment of hypogonadism. Conclusions Despite the 2009 “black box” warning issued by the United States Food and Drug Administration (FDA) regarding potential consequences of transdermal testosterone exposure to women and children, this continues to be an important cause of sexual precocity in children. Children are often subjected to unnecessary and costly evaluation before this exposure is recognized, underscoring the importance of obtaining a thorough medical, family, and social history tailored to the differential diagnosis.