Cryptorchidism is a term used to describe the failure of descent of the testicle into the scrotum. This condition is common among premature boys, 33% of them, and can still be identified in full-term boys in approximately 5%. Ultrasonography can help localize inguinal testicles, while abdominal magnetic resonance imaging or laparoscopy can identify non-palpable intraabdominal testis. Hormonal treatment is indicated at 6 months of life and surgical correction is needed if hormonal therapy failed. Surgical treatment should be attempted before one year of life to achieve better fertility outcome.

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Definition and Epidemiology of Cryptorchidism

Cryptorchidism can be defined as failure of testicular descent into the scrotum. Several forms of undescended testis exist and true cryptorchidism means that the testicle is not palpable. The testicle can be either intra-abdominal or completely absent.

Undescended testis is a common condition especially in preterm boys. One third of preterm boys are expected to have undescended testis while only 5% of full-term boys might have cryptorchidism.

At 3 months of age, only 1% of full-term boys still have an undescended testis. Endogenous production of testosterone is believed to be responsible for the descent of the testis in the first three months of life in 80% of the cases. At six months of age, boys who still have an undescended testis are highly unlikely to have spontaneous descent.

Etiology of Cryptorchidism

The exact cause of cryptorchidism is still unknown; however, several risk factors have been linked to the condition. The most common risk factor is premature birth and/or a birth weight that is lower than 2.5 kg. The testes are formed intra-abdominally and they undergo a highly regulated descent process to eventually reside in the scrotum. Premature boys simply did not complete this normal descent process.

Placental insufficiency and low maternal estrogen levels have also been linked to the development of cryptorchidism.

Environmental factors include organochlorine, mono-esters of phthalates, maternal smoking and maternal diabetes mellitus, which all have been linked to an increased risk of undescended testis and maldevelopment of the male reproductive system.

Pathophysiology of Cryptorchidism

Several theories exist to explain how cryptorchidism might happen. An anatomical structure called the gubernaculum testis is responsible for widening the inguinal canal and guiding the descent of the testis into the scrotum. This structure should be normally attached to the scrotum and tunica vaginalis. Any abnormality in the attachment or configuration of this structure can lead to cryptorchidism.

Additionally, patients with gastroschisis and other conditions with malfunctioning or absence of abdominal wall muscles are known to have low intra-abdominal pressure. This is hypothesized to be responsible for maldescent of the testis in this group of patients.

The undescended testis can have anatomical or functional abnormalities which can be confirmed by histologic examination. These abnormalities might cause the testis to fail to descend and are also responsible for the increased risks of infertility and testicular cancer in the affected testis.

Finally, premature boys can have undescended testis because the testes simply did not start or complete their course to the scrotum. The testes remain inside the abdominal cavity, retroperitoneally, until 28 weeks of gestation.

Clinical Presentation of Cryptorchidism

Testicular examination is the key to diagnose patients with cryptorchidism. Cold hands, sudden palpation and anxiety can activate the cremasteric reflex causing the testis to retract upwards and into the inguinal outer opening. Therefore, examination should be performed with two hands to push the testis downwards, should be gentle and with warm hands. Even with these measures, testicular examination in this age group remains a challenge and should be performed by an experienced pediatric urologist if possible.

During examination, it is important to differentiate between gliding testicle and hypermobile testicle. Once the testicle is pushed down to the scrotum, the examining doctor can remove his or her hand from the inguinal opening. If the testicle returns immediately to the inguinal canal and disappears from the scrotum without activating the cremasteric reflex, the term gliding testicle is used.

If the testicle does not go back to the inguinal opening until the cremasteric reflex is activated, the term hypermobile testicle is used and is thought to be a normal phenomenon.

Several forms of undescended or maldescended testis exist and the table below summarizes them.

Term Definition
Cryptorchidism The testis is completely not palpable because it is either inside the abdominal cavity or because it is completely absent.
Undescended testis The testis can be palpated in the inguinal canal or intra-abdominally visualized by other means such as ultrasonography, and the gubernaculum is normally attached between the lower border of the tunica vaginalis and scrotum.
Ectopic testis The testis is not on its normal descent pathway. It can be under the skin, on the thigh or on the shaft of the penis.

Table 1: Definition of different forms of undescended or maldescended testis.

Diagnostic Work-up for Cryptorchidism

Laboratory investigations are not needed unless the patient has bilateral undescended testicles. In this case, karyotyping is indicated to exclude a female karyotype with adrenogenital syndrome.

Patients with a non-palpable unilateral undescended testis should undergo ultrasonography, magnetic resonance imaging or laparoscopy to determine the presence and structure of the testis.

Ultrasonography has good sensitivity and specifity for detection of an inguinal undescended testicle but might prove to be more difficult for intra-abdominal testicles. Magnetic resonance imaging can visualize non-palpable intra-abdominal testicles but laparoscopy is recommended because it can be both diagnostic and therapeutic.

Treatment of Cryptorchidism

Treatment of undescended testis is dependent mainly on the location of the testis. The first step is wait and see until the infant is six months old because as we have explained, 4 out of 5 patients might have spontaneous descent.

The next step in the management of inguinal testis that is palpable is to prescribe hormonal therapy. Either human chorionic gonadotropin or gonadotropin releasing hormone can be used as both of them lead to increased testosterone production by Leyding cells of the testis. Increased testosterone production is thought to be responsible for the descent of the testis in some patients.

At one year of life, if the testis is not yet in the scrotum, hormonal therapy is deemed to be unsuccessful and surgical treatment is indicated. Surgical treatment involves an orchidopexy in which the testis is fixated to the scrotum.

Patients with non-palpable intra-abdominal testis are recommended to undergo a laparoscopy which is both diagnostic and therapeutic. During laparoscopy, the testis should be identified and fixated to the scrotum. Success rate of laparoscopic orchidopexy is 90%.

Unfortunately, a significant proportion of patients with previous history of cryptorchidism develop subfertility. Additionally, men with previous history of cryptorchidism have a 32-fold increase in risk of testicular malignancy in the affected testicle. This risk is highest for intra-abdominal testicles.

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