Cryptorchidism refers to an absence of a testis (or testes) in the scrotal sac. It may refer to an undescended testis, ectopic testis, or an atrophic or absent testis. Correct localization of the testes is essential because surgical management varies on location.
The testes develop in the abdomen and at ~21 weeks of gestation migrate toward the inguinal canal through the deep inguinal ring. The migration is complete at ~30 weeks. The gubernaculum is the ligament which connects the testes to the scrotum. Under hormonal influence (probably testosterone), the gubernaculum contracts, and the testes descend into the scrotum. Causes/associations of undescended testes are:
- premature birth (birth occurs before full descent of testes)
- intrauterine growth restriction (IUGR)
- associations with smoking, alcohol intake during pregnancy
- androgen insensitivity syndrome
- congenital syndromes
- gestational diabetes
Ultrasound has 45% sensitivity, 78% specificity, and 88% accuracy for localization of an undescended testis and is more accurate than clinical examination 4,5.
- lack of a testis in the scrotal sac
- the undescended testis is a homogeneously hypoechoic ovoid structure, similar to the contralateral testis, with an echogenic mediastinum testis
- the ectopic testis may be high up in the scrotum or within the inguinal canal (39%)
- ultrasound is limited in intra-abdominal, pelvic or retroperitoneal/ectopic testes (20%)
- ultrasound is also inconclusive in evaluation of the atrophic testis (41%), where it is difficult to differentiate from lymph nodes or the pars infravaginalis gubernaculi 1
MRI is the best cross-sectional modality to assess crypto-orchidism (replacing CT). It has a higher sensitivity than ultrasound (~90%) and a higher specificity (100%) 6.
Coronal T1W images can show the gubernaculum testes and spermatic cord, which can be followed to locate the undescended testes. Also, an ectopic pelvic or retroperitoneal location of testes can be identified. Diffusion-weighted MRI shows the normal testes as markedly hyperintense structures, differentiating them from surrounding structures 2.
Treatment and prognosis
Most undescended testes at birth descend in the first three months after birth
Orchiopexy is the preferred mode of management in case of viable testes high-up in the scrotum or within inguinal canal / abdomen. It is performed after 1 year of age since the testes may descend without intervention.
With cryptorchidism there is a 32x increased risk of developing a testicular germ cell tumor, with an incidence of 1 in 2000 (higher in bilateral cases, and in abdominal cryptorchidism) 7. The effect of surgical correction, decreasing the risk of malignancy is controversial but it does allow for easier examination 7, and - hopefully - earlier detection.
An exaggerated cremasteric reflex can simulate cryptorchidism.
- 1. Frush DP, Sheldon CA. Diagnostic imaging for pediatric scrotal disorders. Radiographics. 18 (4): 969-85. Radiographics (abstract) - Pubmed citation
- 2. Kantarci M, Doganay S, Yalcin A et-al. Diagnostic performance of diffusion-weighted MRI in the detection of nonpalpable undescended testes: comparison with conventional MRI and surgical findings. AJR Am J Roentgenol. 2010;195 (4): W268-73. doi:10.2214/AJR.10.4221 - Pubmed citation
- 3. Moore KL, Persaud TVN, Torchia MG. The Developing Human: Clinically Oriented Embryology with Student Consult Online Access, 9th Edition. Saunders. ISBN:1437720021. Read it at Google Books - Find it at Amazon
- 4. Tasian GE, Copp HL, Baskin LS. Diagnostic imaging in cryptorchidism: utility, indications, and effectiveness. J. Pediatr. Surg. 2011;46 (12): 2406-13. doi:10.1016/j.jpedsurg.2011.08.008 - Free text at pubmed - Pubmed citation
- 5. Adesanya OA, Ademuyiwa AO, Evbuomwan O et-al. Preoperative localization of undescended testes in children: comparison of clinical examination and ultrasonography. J Pediatr Urol. 2014;10 (2): 237-40. doi:10.1016/j.jpurol.2013.09.023 - Pubmed citation
- 6. Yeung CK, Tam YH, Chan YL et-al. A new management algorithm for impalpable undescended testis with gadolinium enhanced magnetic resonance angiography. J. Urol. 1999;162 (3 Pt 2): 998-1002. Pubmed citation
- 7. Mathers MJ, Sperling H, Rübben H et-al. The undescended testis: diagnosis, treatment and long-term consequences. Dtsch Arztebl Int. 2009;106 (33): 527-32. doi:10.3238/arztebl.2009.0527 - Free text at pubmed - Pubmed citation
Related Radiopaedia articles
Ultrasound - testicular and scrotal
- ultrasound (introduction)
testicular and scrotal ultrasound
unilateral testicular lesion
- testicular torsion
- testicular rupture
- germ cell tumors of the testis
- sex cord / stromal tumors of the testis
- testicular cyst
- testicular lymphoma
- bilateral testicular lesion
- paratesticular lesions
- tubular ectasia of the rete testis
- cystadenoma of the rete testis
- testicular sarcoidosis
- testicular tuberculosis
- spermatic cord
- fibrous pseudotumour of the scrotum
- scrotal leiomyosarcoma
- testicular adrenal rest tumors (TARTs)
- tunica vaginalis testis mesothelioma
- splenogonadal fusion
- testicular vasculitis
- unilateral testicular lesion