Introduction
Background
Cryptorchidism is defined as failure of the testis to descend from its intra-abdominal location into the scrotum. The exact etiology of cryptorchidism is not known. In one third of patients, the condition is bilateral. Ultrasound (US), CT, MRI, arteriography, and laparoscopy are used for diagnosis.
Orchiopexy is the treatment of choice and usually is performed in patients aged 2-10 years. A cryptorchid testis is 20-48 times more likely to undergo malignant degeneration than a normal testis. Orchiopexy does not alter the risk of malignant transformation. The incidence of malignant transformation also is increased in the unaffected testis. Consider hormone treatment with either human chorionic gonadotropin or gonadotropin-releasing hormone analogues for palpable high-scrotal position of the testis; however, efficacy is less than 20%. Surgical treatment is most effective and reliable.
Pathophysiology
A normal testis develops in the celomic cavity and begins to descend into the scrotum at 36 weeks, guided by the contractile cordlike structure termed the gubernaculum testis. The distal bulbous portion of the gubernaculum testis is termed the pars infravaginalis gubernaculi. After complete descent into the scrotum, the gubernaculum testis atrophies; however, it persists if the descent is not complete.
Frequency
United States
Incidence in premature male infants is 9.2-30%. In full-term infants, the incidence is 3.3-5.8%, and in infants aged 1 year, it is 0.8%.
International
Refer to frequency in the US.
Mortality/Morbidity
The lifetime risk of death from testicular malignancy in men of any age with undescended testis is approximately 9.7 times the risk in men with normally descended testis.
- Infertility: This condition is observed in 40% of patients with unilateral and 70% of patients with bilateral cryptorchidism.
- Malignant degeneration: Testicular malignancies occur in 10% of men with cryptorchid testis. The incidence of malignant degeneration in an undescended testis is reportedly as high as 48 times greater than in a normal testis. Seminoma is the most commonly reported malignancy.
- Torsion: This rare condition, if present, usually is secondary to the presence of a mass.
Race
No racial predilection is known.
Sex
Cryptorchidism is observed only in males.
Age
Cryptorchidism usually presents at birth or by preadolescence; however, it can present at any age. Avoid intervention before age 1 year because of the possibility of spontaneous descent.
Anatomy
Testicular size depends on age and stage of sexual development. Before age 12 years, testicular volume is 1-2 mL. Mean testicular volume at age 16 years is 14 mL.
US is the most frequently used imaging study for the testicle. On US, prepubertal testes are of low-to-medium level echogenicity. A normal adult testis has medium level echoes and measures 5 X 3 X 2 cm. The tunica albuginea is the fibrous covering of the testicle. Septa extend from the tunica albuginea into the testicle, dividing the testes into lobules. The posterior surface of the tunica albuginea is reflected into the interior of the gland, forming the incomplete septum termed the mediastinum of the testis. Sonographically, this is seen as an echogenic band running across the testis.
Each lobule is composed of many seminiferous tubules that open via tubules (tubuli recti) into dilated spaces termed the rete testes within the mediastinum. These in turn communicate via efferent ductules in the epididymal head. The epididymis is composed of a head, body, and tail, the ducts of which continue as the vas deferens in the spermatic cord.
Presentation
Patients present with the condition or the parents bring the child with nonpalpable testis.
Physical examination reveals a nonpalpable testis in the scrotum. The most common location of the cryptorchid testis is in the inguinal canal (72%), followed by prescrotal (20%) and abdominal (8%) locations.
The primary treatment of cryptorchid testis is orchiopexy.
Preferred Examination
US is the first imaging modality performed on a cryptorchid testis for the following reasons:
- Of cryptorchid testes, 72% are in the inguinal canal; therefore, they are easily accessible to US examination.
- US is readily available.
- US is easy to schedule.
If US cannot identify the testis (US effectively detects cryptorchid testis below the level of the internal inguinal ring), MRI and CT are the subsequent modalities of choice. Both can detect an abdominal testis.
Laparoscopy is performed if MRI and CT cannot localize the testis.
Limitations of Techniques
- US cannot detect an intra-abdominal testis.
- CT uses radiation and does not have multiplanar capability.
- MRI has better soft-tissue contrast and multiplanar capability; however, when the testis is higher in the abdomen, the presence of bowel loops lowers the sensitivity for detecting the cryptorchid testis.
- Laparoscopy is invasive and expensive.
Differential Diagnoses
Other Problems to Be Considered
Testicular ectopia (normal descent but abnormal location, such as perineum, femoral, suprapubic regions; in nonpalpable testis in the scrotum search these areas to exclude ectopia, which is rare in the contralateral hemiscrotum)
Retractile testis (often bilateral, normal condition; commonly seen in prepubertal boys; absent in adults)
Congenital absence (anorchia; rare, 4% of patients who clinically have an undescended testis actually have unilateral absence)
Atrophic testis (usually secondary to torsion; no color flow Doppler or contrast enhancement seen)
Lymph node (fatty hilum, characteristic location adjacent to vessels helps identification)
Pars infravaginalis gubernaculi (occasionally mistaken for testis)
Hypospadias and inguinal hernia (associated conditions)
More on Cryptorchidism |
 Overview: Cryptorchidism |
| Imaging: Cryptorchidism |
| Follow-up: Cryptorchidism |
| Multimedia: Cryptorchidism |
| References |
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References
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Further Reading
Keywords
undescended testis, maldescended testis, atrophic testis, anorchia
