Testis & paratestis

Nonneoplastic lesions


Last author update: 1 March 2015
Last staff update: 12 April 2021

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PubMed search: Endometriosis testis

Swapnil U. Rane, M.D.
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Cite this page: Rane S. Endometriosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/testisepidmisc.html. Accessed August 17th, 2022.
  • Epididymis, prostate
Etiology and Pathophysiology
  • Arises within remnants of Müllerian ducts (prostatic utricle and appendix testis)
  • Most cases have been associated with estrogen therapy for prostrate carcinoma
  • May arise in setting of chromosomal abnormalities affecting Müllerian inhibitory substance / MIS gene, in abnormalities of MIS secretion, gonadal dysgenesis and renal dysgenesis associated with abnormalities of Müllerian duct
Clinical features
  • Usually incidental finding
Case reports
  • Excision is curative
Gross description
  • Small, single to multiple, unilocular or multilocular hemorrhagic cysts within epididymis, paratesticular region or rarely in testis
Microscopic (histologic) description
  • A true cyst lined by cuboidal to columnar epithelium with hemosiderin laden macrophages in stroma
  • Lumen contains hemorrhagic fluid
  • Endometrial stroma may not be conspicuous but is usually present
  • The epithelium stain for cytokeratins CK7, CK8, CK18
  • The stromal cells are usually positive for ER, PR and CD10
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