Testicular regression is also known as testicular regression syndrome, anorchia, empty scrotum, and vanishing testes. Different than simply undescended testicles, the gonads are undeveloped and absent.
The condition may be caused hormonally or, as evidenced by the presence of spermatic cord structures, from some early torsion and atrophy of the developing testes in the womb.
Diagnosis is made based on the observable lack of testes, and, though the child is genetically male, he will have low testosterone levels, elevated FSH and LH levels, low anti-Müllerian hormones, and low bone density.
Treatment typically includes testosterone supplementation at puberty, testicular prostheses, and psychological support.