Testis & paratestis
Development
Testicular regression syndrome / anorchia
Last author update: 1 September 2012
Last staff update: 9 September 2020
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PubMed Search: Anorchia [title] OR testicular regression [title]
Table of Contents
Definition / general | Etiology | Testicular regression syndrome | Case reports | Microscopic (histologic) description | Microscopic (histologic) imagesCite this page: Al-Hussain T, Williamson S. Testicular regression syndrome / anorchia. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/testistesticularregression.html. Accessed January 20th, 2025.
Definition / general
- Anorchism: absence of both testis
- Monoorchidism: absence of one testis
- Testicular regression syndrome: phenotypically normal male with vas deferens is present
Etiology
- Causes: cryptorchidism, possibly testicular infarct, infection, trauma, torsion or prenatal hormone induced atrophy due to overproduction of androgens
Testicular regression syndrome
- Either no gonadal or testicular formation or regression of testicular tissue with residual fibrovascular nodule (mean 1.1 cm), calcification and hemosiderin
- Rudimentary epididymis and spermatic cord are present
- External genitalia depends on chronology of gonadal injury
Case reports
- 1 year old boy with undescended testis and firm nodule near external inguinal opening (Case of the Week #279)
Microscopic (histologic) description
- Regressed testis indicated by fibrosis, hemosiderin, calcification or Leydig cells near epididymis or proximal vas deferens (Arch Pathol Lab Med 2000;124:694)
- Presence of only fat and connective tissue does not rule out an intraabdominal testis
Microscopic (histologic) images
Case #279
