Kiarash Taghavi, FRACS(Paed Surg), Anthony Chin, MD, Jayant Radhakrishnan, MB, BS, MS(Surg)


Cryptorchidism or undescended testis (UDT) is defined clinically as a testis that has a mechanical impediment to being brought to the bottom of the scrotum. Undescended testis may be classified in many ways: palpable or impalpable, congenital or acquired (i.e. ascending or iatrogenic), syndromic or nonsyndromic, unilateral or bilateral, ectopic or undescended along the path of normal descent. In the vast majority of UDT, the cause of maldescent is unknown [1]. Impalpable UDT most commonly refers to a testis that is present in a canalicular or intra-abdominal position although further investigation may identify a completely absent testis. In this situation the testis is most commonly referred to as vanishing or regressed - consistent with the fact that it was present initially but disappeared during development (most likely due to a vascular incident) [2][3][4].

The testis is a mobile organ and a retractile testis must be clarified. The retractile testis resides spontaneously in the scrotum at least some of the time. All prepubertal boys have some degree of retractility to their testes; this is due to the relatively small volume of the prepubertal testis such that the cremasteric contraction contributes a more significant moment on the testis. Furthermore, at birth the cremasteric reflex is either absent or extremely weak and is most pronounced between three to nine years [5].

The main reasons for treatment of cryptorchidism include optimizing fertility potential and psychosexual development, preventing testicular malignancy, preventing torsion and/or treating an associated inguinal hernia [2]. The current standard of therapy is orchidopexy (surgical repositioning of the testis within the scrotal sac). Hormonal therapy has few advocates and poor efficacy. Successful scrotal relocation of the testis reduces, but does not completely negate, potential long term sequelae in susceptible individuals.

Content in this topic is referenced in SCORE Undescended Testicle (Cryptorchidism) overview

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Last updated: January 20, 2022