Testes in infants with Prader-Willi syndrome: human chorionic gonadotropin treatment, surgery and histology

PURPOSE: Boys with Prader-Willi syndrome often have undescended testes. Prospective studies on the treatment of cryptorchidism in these patients are lacking. We evaluated the effects of human chorionic gonadotropin administration on testis position in 16 males with Prader-Willi syndrome. In patients who subsequently underwent orchiopexy biopsy was taken and testis histology was evaluated.

MATERIALS AND METHODS: A total of 16 boys (median age 1.6 years, IQR 1.2 to 1.8) with Prader-Willi syndrome and cryptorchidism underwent human chorionic gonadotropin stimulation test. After a positive test human chorionic gonadotropin treatment was initiated. Patients received 250 to 500 IU (depending on age) intramuscularly twice weekly for 6 weeks.

RESULTS: We found 1 testis in a stable scrotal position, 1 vanished testis and 1 atrophic abdominal testis. Of 29 testes responding to human chorionic gonadotropin 23% reached a stable scrotal position, 62% reached a lower position and 14% did not change position. Thus, 22 testes required orchiopexy. Of 17 obtained biopsies in 12 patients 2 showed germ cells in more than 60% of seminiferous tubules, 3 in 30% to 60% and 7 in less than 30%. In addition, 4 boys had Sertoli cell only syndrome and 1 had a vanished testis. In patients undergoing orchiopexy younger age and increased inhibin B and testosterone levels after human chorionic gonadotropin stimulation were associated with a greater number of germ cell containing tubules.

CONCLUSIONS: Human chorionic gonadotropin administration resulted in an anatomically lower testis position in most of our patients with Prader-Willi syndrome, and 23% of testes reached a stable scrotal position. Of the cases 76% required orchiopexy to ensure a stable position in the scrotum.