Editing AUA: Cryptorchidism (2018) (section)

== Background ==

* '''Epidemiology'''
** '''<span style="color:#ff0000">Most common genital disorder identified at birth'''
***'''<span style="color:#ff0000">Prevalence among newborns:'''
****'''<span style="color:#ff0000">1-3% in full-term'''
****<span style="color:#ff0000">'''15-30% in premature male infants'''
**Spontaneous descent of congenitally cryptorchid testes occurred in 35-43% of newborn boys followed longitudinally, usually prior to 3 months of age
***'''Descent of the testes into the scrotum is probable in premature boys during the first months of life, but is unlikely after 6 months of corrected age'''
****'''<span style="color:#ff0000">Obtaining the gestational age is thus critical to the proper and timely referral of a child with persistent undescended testes to a surgical specialist'''
*'''Normal Testicular Descent''' 
**'''Occurs in 2 phases:''' 
**#'''Transabdominal descent'''
**#'''Inguinoscrotal migration'''
**Transabdominal descent
***occurs in the first trimester of gestation
***At approximately 22-25 weeks of gestational age, the testes are located at the internal ring
**'''Inguinoscrotal migration'''
***Occurs between 25-30 weeks
***Androgen dependent
*'''Usually unilateral (70-80%)'''
**Approximately 20-30% of all patients with cryptorchidism have bilateral UDTs.
*'''<span style="color:#ff0000">Potential location of cryptorchid testes (4):'''
*# '''<span style="color:#ff0000">Prescrotal (above or at the scrotal inlet)'''
*# '''In the superficial inguinal pouch (distal and lateral to the external inguinal ring, anterior to the rectus muscle), at the external ring (or prepubic)'''
*# '''<span style="color:#ff0000">Within the inguinal canal'''
*# '''<span style="color:#ff0000">Ectopic'''
*#* '''<span style="color:#ff0000">Most commonly perineal'''
*#* '''Abdominal''' 
*#** "Peeping" through or proximal to the internal inguinal ring
*#** Near the bladder, iliac vessels or kidney
*'''<span style="color:#ff0000">A genital examination should be performed at least annually at every well-child visit in accordance with Bright Futures AAP recommendations.'''
**Testicular position may change as infants and children grow.