One or both testes may be absent from the scrotum at birth in about 20% of premature or low-birth-weight male infants and in 3–6% of full term infants. Cryptorchidism is found in 1–2% of males after 1 year of age but must be distinguished from retractile testes, which require no treatment. Infertility or subfertility occurs in up to 75% of men with bilateral cryptorchism and in 50% of men with unilateral cryptorchism. Some patients have underlying hypogonadism, including hypogonadotropic hypogonadism.
For a testis that is not palpable, it is important to locate the testis and bring it into the scrotum or prove its absence. About one-third of nonpalpable testes are located within the inguinal canal, one-third are intra-abdominal, and one-third are absent. Ultrasound can detect an inguinal testis. If ultrasound is negative, MRI is performed to locate the testis. Surgery for cryptorchid testes (orchiopexy) should be performed by age 12–24 months and is generally successful. Alternatively, hCG, 1500 units intramuscularly daily for 3 days, causes a significant rise in testosterone if the testes are present. Therapy with hCG results in a testicular descent rate of about 25%.
The lifetime risk of testicular neoplasia is 0.002% in normal males. The risk of malignancy is higher for cryptorchid testes (0.06%) and for intra-abdominal testes (5%). Orchiopexy decreases the risk of neoplasia when performed before 10 years of age. Orchiectomy after puberty is an option for intra-abdominal testes.
et al. Genetic, maternal, and environmental risk factors for cryptorchidism: an update. Eur J Pediatr Surg. 2016 Oct;26(5):399–408.
et al. Nonpalpable testes: ultrasound and contralateral testicular hypertrophy predict the surgical access, avoiding unnecessary laparoscopy. J Pediatr Urol. 2018 Apr;14(2):163.e1–7.
et al. Association between male genital anomalies and adult male reproductive disorders: a population-based data linkage study spanning more than 40 years. Lancet Child Adolesc Health. 2018 Oct;2(10):736–43.
et al. Molecular mechanisms of cryptorchidism development: update of the database, disease comorbidity, and initiative for standardization of reporting in scientific literature. Andrology. 2016 Sep;4(5):894–902.