Editing AUA: Cryptorchidism (2018) (section)

== Definitions ==

* '''<span style="color:#ff0000">Cryptorchidism, or undescended testis (UDT): failure of a testis to descend into a scrotal position'''
** '''<span style="color:#ff0000">Classified as congenital vs. acquired'''
*** '''Congenital cryptorchidism: testes that are extrascrotal from the time of birth'''
*** '''Acquired cryptorchidism:  testes are intrascrotal at birth but subsequently identified in an extrascrotal position'''
**** '''Classified as ascending vs. entrapped'''
***** '''Ascending: spontaneous change from an intrascrotal to an extrascrotal position occurs at some point after birth'''
******'''Generally unilateral and most likely located distal to the inguinal ring'''
***** Entrapped: change from an intrascrotal to an extrascrotal position occurs after prior inguinal surgery
****At risk for developing the same adverse histologic changes seen in primary cryptorchid testes
** '''Retractile testis: testis that is initially extrascrotal on examination or moves easily out of scrotal position but that can be manually replaced in stable, dependent scrotal position and remain there without tension at least temporarily'''
***'''Often associated with a vigorous cremasteric reflex'''
* '''Atrophic testis: testis that suffers significant volume loss due to'''
*# Prior inguinal or testicular surgery OR
*# Due to prolonged location in an extrascrotal position OR
*# Primary developmental failure
* '''<span style="color:#ff0000">Vanished testis: testis was present initially but disappeared during development most likely due to spermatic cord torsion or vascular accident'''