THE UNDESCENDED TESTICLE

There are many explanations for the mechanism of testicular descent but none are fully satisfactory. Testicular descent is a process that begins in the fourth and fifth week of fetal life and is completed between the seventh month of gestation and one month after birth. Complete descent requires an intact hypothalamic-pituitary-gonadal axis. The responsible portions of the central nervous system and the end organ (the testicle) must be capable of producing and receiving the necessary hormones or neural stimuli and must do so in the appropriate time frame. The developing inguinal canal and gubernaculum must permit testicular descent.

With a more complete understanding of the mechanism of testicular descent and testicular physiology, it is evident that if we have any positive impact on the undescended testicle (UDT), it is by early surgical correction. Significant cellular damage is present by age one year, and for that reason, we believe that the child with an undescended testicle should be referred by six months of age and the repair performed by one year of age. A very small percentage of children with an UDT will have a testicle descend spontaneously in the first few months of life. The undescended testicle is also associated with hernias in a moderate percentage of children, and parents should be advised of the symptoms of incarcerated hernia if repair of the UDT is to be delayed. The presence of a hernia warrants immediate correction. A distinction should be made between the undescended testicle and the impalpable testicle--especially in cases of bilateral involvement. Those patients with bilateral impalpable testes will need an endocrine evaluation to determine whether functioning testicular tissue is present.

Once corrected, the undescended testicle is still at risk for malignancy, and the patient should be monitored with an annual genital examination and should be taught testicular self-examination. The risk of malignancy is probably reduced by early correction. High-risk patients are those with intra-abdominal testicles or testes that have been brought down after early childhood. Early correction appears to maximize the child's potential for fertility.

The incidence of testicular maldecensus is rising as evidenced by several studies from around the world. The reason for this rise is not clear, but it may be caused by environmental pollutants and estrogen-like chemicals.

The retractile testicle is a condition that must be differentiated from the undescended testicle. The retractile testicle is one that can be manipulated into a dependent scrotal position. The differentiation between these conditions is important as the retractile testicle requires no surgical therapy and is not prone to infertility or testicular cancer, as is the truly undescended testicle. These conditions can be distinguished with a HCG stimulation test. A short course of HCG will cause the retractile testicle to descend normally. The truly undescended testicle will not. Patients with retractile testicles should be followed until the testicle remains in the scrotum spontaneously.