2020 Edition
| Editors: Maria Rosaria Raspollini, Antonio Lopez-Beltran

Anorchism, Testicular Regression Syndrome

  • Manuel NistalEmail author
  • Pilar González-Peramato
Reference work entry
DOI: https://doi.org/10.1007/978-3-030-41894-6_4781


Monorchidism; Testicular regression syndrome (TRS)


Anorchidism is defined as the absence of one (monorchidism) or both testes (testicular regression syndrome) in males with 46, XY karyotype. The monorchidism may be due to a congenital absence of testis or a loss of it (vanishing testis).

Clinical Features

Patients with absence of one testis show no other symptoms than an empty scrotum. The diagnosis is confirmed by laparoscopy when observing blind-ended vas deferens and presence of spermatic vessels. In some patients compensatory hypertrophy of the contralateral testis is observed (more than 2 cm3) (Grinspon et al. 2016).

Testicular regression syndrome (TRS) refers to different situations in which patients show from a female phenotype (congenital bilateral absence of testis) to male phenotype (some microorchies and involutions of both testes). Depending on the moment of fetal life in which the testis disappeared, the following syndromes develop: rudimentary testis...

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References and Further Reading

  1. Dangle, P., Salgado, C., Reyes-Mugica, M., Schneck, F., Ost, M., & Sims-Lucas, S. (2017). Testicular hypoplasia is driven by defective vascular formation. Urology, 101, 94–98.CrossRefGoogle Scholar
  2. Grinspon, R. P., Habib, C., Bedecarrás, P., Gottlieb, S., & Rey, R. A. (2016). Compensatory function of the remaining testis is dissociated in boys and adolescents with monorchidism. European Journal of Endocrinology, 174, 399–407.CrossRefGoogle Scholar
  3. Hunter, J. D., Pierce, S. R., Calikoglu, A. S., & Howell, J. O. (2016). Embryonic testicular regression syndrome presenting as primary amenorrhea: A case report and review of disorders of sexual development. Journal of Pediatric and Adolescent Gynecology, 29, e59–e62.CrossRefGoogle Scholar
  4. Nataraja, R. M., Yeap, E., Healy, C. J., Nandhra, I. S., Murphy, F. L., Hutson, J. M., & Kimber, C. (2018). Presence of viable germ cells in testicular regression syndrome remnants: Is routine excision indicated? A systematic review. Pediatric Surgery International, 34, 353–361.CrossRefGoogle Scholar
  5. Vandewalle, S., Van Caenegem, E., Craen, M., Taes, Y., Kaufman, J. M., & T’Sjoen, G. (2018). Growth, sexual and bone development in a boy with bilateral anorchia under testosterone treatment guided by the development of his monozygotic twin. Journal of Pediatric Endocrinology & Metabolism, 31, 361–367.CrossRefGoogle Scholar

Copyright information

© Springer Nature Switzerland AG 2020

Authors and Affiliations

  1. 1.Department of Anatomy, Histology and Neuroscience, School of MedicineUniversidad Autónoma de MadridMadridSpain
  2. 2.Department of PathologyUniversidad Autónoma de MadridMadridSpain
  3. 3.Department of PathologyUniversity Hospital La PazMadridSpain