Histological analysis of testes in patients with 5 alpha-reductase deficiency type 2: Comparison with cryptorchid testes in patients without endocrinological abnormalities and a review of the literature.

As evidenced by the intact histology of the testes during infancy, testicular differentiation during the prenatal period occurs normally in individuals with 5 alpha-reductase type 2 deficiency (5αRD); however, a majority of these individuals suffer from azoospermia or oligospermia during adulthood, indicating that impaired spermatogenesis occurs postnatally. Although the accompanying cryptorchidism may be partly responsible for this process, the underlying mechanisms remain largely unknown. To address this issue, we retrospectively compared the histological findings of descended testes in a 3-mo-old patient and undescended testes in an 18-yr-old patient with 5αRD. In the latter, testicular histology was compared to that of cryptorchid testes obtained from five adolescent patients without endocrinological abnormalities. Histological findings of a 3-mo-old patient revealed normal number of germ cells with intact seminiferous tubules. In contrast, an 18-yr-old patient showed marked reduction in germ cell number and atrophic seminiferous tubules. The findings were very similar to those observed in cryptorchid testes without endocrinological abnormalities. These findings suggest that the decrease in germ cells in 5αRD patients may be at least partly caused by accompanying cryptorchidism. As the number of germ cells did not decrease during the infantile period, early orchiopexy is recommended to prevent a decrease in germ cell number and preserve fertility.