RESUMEN
OBJECTIVE@#To investigate the efficacy and safety of aromatase inhibitor letrozole in treatment of male children with disorders of sex development (DSD).@*METHODS@#Clinical data of 12 male DSD children with a mean age of 14.6±2.5 years admitted to Peking Union Medical College Hospital from January 2014 to January 2016 were retrospectively analyzed. The patients were treated with letrozole (1.25-2.5 mg, once a day) for 3 months or longer, and followed up for 0.5-2.5 years. Clinical manifestation and laboratory test findings were documented, and the efficacy and safety were evaluated.@*RESULTS@#After half-year treatment, the blood luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone levels of patients increased (all < 0.05), and estrogen levels decreased from baseline ( < 0.05). After 1 year of treatment, the blood testosterone level was significantly higher ( < 0.05); the LH and FSH levels tended to increase and the estrogen level tended to decrease, but there was no significant statistical difference ( >0.05). Semen was routinely detected in 8 patients, and sperms were detected in semen of 3 patients with hypospadias. There were no significant changes in biochemical results after treatment, and no significant adverse event was observed during the treatment.@*CONCLUSIONS@#Letrozole can effectively increase testosterone levels in patients with disorders of sex development and promote spermatogenesis, it has no significant adverse effects in short-term administration.