Quantitative histology of germ cells in the undescended testes of human fetuses, neonates and infants

PURPOSE: We investigated the number of germ cells per tubular cross section and testicular weight in cryptorchid fetuses, neonates and infants, and characterized additional abnormalities.

MATERIALS AND METHODS: Our series comprised 35 fetuses and 58 boys with cryptorchidism, and 22 normal fetuses and 25 normal boys. Age ranged from 28 weeks of gestation to 3 years.

RESULTS: Cryptorchid fetuses had reduced germ cells per tubular cross section values and lower testicular weights. Values were reduced in cryptorchid boys without a symptomatic inguinal hernia. If a hernia was present, values were normal in the first year of life but decreased at age 1 to 3 years. Malformations or dysplasia of the kidneys, ureter or T10 to S5 vertebrae were present in 34% of the cryptorchid fetuses and 18% of the cryptorchid boys without a symptomatic inguinal hernia.

CONCLUSIONS: Our study suggests a reduced number of germ cells in undescended testes from week 28 of gestation and germ cell hypoplasia as a consequence of continued postnatal undescended testicular position. Cryptorchidism may result from abnormal development of the caudal developmental field.