Clinical and metabolic findings in a 6-year-old boy with a Leydig cell tumour.

To analyse the urinary steroid metabolome in a boy who had true precocious puberty after a Leydig cell tumour. Case report and detailed description of clinical and metabolic findings in a 7-year-old-boy with a Leydig cell tumour. Before surgery, the urinary steroid metabolome showed an activation of an alternative route to gonadal androgens independent of dehydroepiandrosterone (DHEA). After surgery, the boy entered true precocious puberty. Under leuprolide acetate treatment, clinical and laboratory findings normalized. Central precocious puberty after precocious pseudopuberty may be more common than expected and should be considered in children with persistent or recurrent symptoms after initial treatment of precocious pseudopuberty. Patients with a Leydig cell tumour seem to reactivate the so-called 'back door pathway' of androgen production, which is independent of the classical route via DHEA.