This blog will review the proposed mechanisms of cryptorchidism and treatment options.
Embryology and EtiologyDuring development of the male embryo, the primitive testicles form near the developing kidneys. As the embryo grows, the testicles remain relatively still while the embryo grows and lengthens. Under the influence of testosterone and other hormones, the testicles exit the abdominal cavity and settle in the scrotum at about the 8th month of pregnancy - explaining why the incidence of cryptorchidism is much higher in premature infants.
There are a number of theories to explain why testicles fail to descend. There are some known genetic causes and approximately 14% of boys with cryptorchidism have a positive family history. Additional support for genetic causes of cryptorchidism include a number of mouse models with culprit genes and the observation that infants with severe congenital syndromes, like congenital adrenal hyperplasia, Klinefelter's disease, autosomal trisomy or disorders of sexual differentiation, will often have cryptorchidism. Maternal obesity is associated with an increased risk of cryptorchidism, as is low birth weight and cesarean section delivery. Finally, environmental exposure to "endocrine disruptors" that elevate estrogens or decrease androgens may affect the ultimate descent of the testicle.
|Locations of undescended testicles.
Retractile TestisRetractile testes are occasionally misdiagnosed for cryptorchidism. Retractile testes are normally descended testicles that ascend or retract into the inguinal region due to a strong cremasteric reflex. The cremaster muscle is the muscle of the spermatic cord that can pull the testicle upward when the inner thigh is stroked. The management for retractile testis is observation as approximately 30% will descend, 40% will remain retractile (but not have any problems), and 30% will ascend and require intervention.
Management of CryptorchidismThere are a number of goals in the management of undescended testicles:
- Preserve fertility
- Prevent and monitor for testis cancer
- Repair inguinal hernia
- Reduce the risk of testicular torsion