Editing Undescended Testicle (section)

== Pathogenesis ==

* '''<span style="color:#ff0000">Classified congenital vs. acquired'''
** '''<span style="color:#ff0000">Distinction based on findings documented during the neonatal exam.'''
*** In congenital cases, the testicle is not palpable in the scrotum at birth
*** In acquired cryptorchidism (or “ascending” testicle) is in a normal location at birth (or on subsequent well-child exams), but not later in life.

=== Congenital ===
* '''<span style="color:#ff0000">Perinatal risk factors (4):'''
*# '''<span style="color:#ff0000">Prematurity'''
*# '''<span style="color:#ff0000">Low birth weight or small size for gestational age'''
*# '''<span style="color:#ff0000">Breech presentation'''
*# '''<span style="color:#ff0000">Maternal diabetes'''
* '''<span style="color:#ff0000">Genetic susceptibility'''
** '''<span style="color:#ff0000">Family history</span>'''; susceptibility is likely polygenic and multifactorial
** Although multiple genetic variants likely contribute to the risk of non-syndromic cryptorchidism, most remain unknown at this time.
* '''<span style="color:#ff0000">Environmental risk factors (4):'''
*# '''<span style="color:#ff0000">Maternal smoking'''
*# '''<span style="color:#ff0000">Maternal use of acetaminophen'''
*# '''<span style="color:#ff0000">Abnormalities in pituitary and/or gonadal hormone secretion during infancy''' in the absence of generalized, persistent endocrine dysfunction
*# '''<span style="color:#ff0000">Environmental chemicals:</span>''' potential associations in selected populations but not strongly supported as a cause of increased susceptibility to cryptorchidism
* '''<span style="color:#ff0000">Syndromic Cryptorchidism'''
** '''Undescended testes are frequently present in diseases associated with reduced androgen production and/or action, such as androgen biosynthetic defects, androgen insensitivity, Leydig cell agenesis, and gonadotropin deficiency disorders'''
** '''Conditions associated with cryptorchidism'''
**# '''<span style="color:#ff0000">Persistent müllerian duct syndrome'''
**#* '''See [[Disorders of Sexual Differentiation]] Chapter Notes'''
**# '''<span style="color:#ff0000">Klinefelter syndrome'''
**#* '''See [[Disorders of Sexual Differentiation]] Chapter Notes'''
**# '''<span style="color:#ff0000">Down syndrome (trisomy 21)'''
**# '''<span style="color:#ff0000">Prune-belly syndrome'''
**# '''<span style="color:#ff0000">Prader-Willi syndrome'''
**# '''<span style="color:#ff0000">Noonan’s syndrome'''
**# '''<span style="color:#ff0000">Myelomeningocele'''
**# '''<span style="color:#ff0000">Posterior urethral valve'''
**# '''<span style="color:#ff0000">Cerebral palsy'''
**# '''<span style="color:#ff0000">Arthrogryposis'''
**# '''<span style="color:#ff0000">Spigelian hernia, omphalocele, gastroschisis, imperforate anus, umbilical hernia'''

=== Acquired ===
* Most likely represents a milder presentation of congenital cryptorchidism that escapes detection in infancy
* '''Diagnosed at an average age of 8 to 11 years'''
* '''More commonly in a lower position, associated with a closed processus vaginalis and normal epididymis, than in cases diagnosed as congenital.'''
* '''May be more likely in boys with retractile testes''' (scrotal testes that retract easily out of the scrotum but can be manually replaced in a stable scrotal position and remain there at least temporarily until there is recurrent stimulation), although testis retractility is common in normal populations