Testis & paratestis

Ovarian type tumors

Serous borderline tumor

Last author update: 1 August 2014
Last staff update: 20 October 2022

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PubMed Search: Serous borderline tumor

Swapnil U. Rane, M.D.
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Cite this page: Rane S. Serous borderline tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/testisserousborder.html. Accessed September 29th, 2023.
Definition / general
  • Serous epithelial tumor of low malignant potential occurring in paratesticular region
  • Same as ovarian counterparts
  • Rare tumor but more common than malignant serous epithelial tumors
  • Mean patient age in the largest reported series was 56 years, range of 14 - 77 years (Am J Surg Pathol 2001;25:373)
  • Tunica is most common site, commonly arising from tunica albuginea
  • Tunica vaginalis, spermatic cord are other common sites
  • Tumor may extend to testis
Etiology and Pathophysiology
  • Postulated cell of origin is Müllerian metaplasia of mesothelial lining
  • Cases arising in testis are explained by Müllerian metaplasia occurring in mesothelial cell inclusions within testicular parenchyma
  • Embryological Müllerian remnants within testis and paratestis are also postulated to give rise to these tumors
Clinical features
  • Painless testicular mass in elderly male is most common presentation
  • Suspected clinico - radiologically and confirmed histologically
  • No specific laboratory abnormality
Radiology description
  • Cystic lesion arising in paratesticular / testicular region
  • Broad papillae may be visualized but there are no specific diagnostic criteria
Prognostic factors
  • No reports of recurrence of serous borderline tumors but lesion is rare and reported follow up is only 2 years
Case reports
  • Radical orchidectomy is treatment of choice
  • No cases reported have recurred with or without chemotherapy but need for adjuvant chemotherapy needs to be assessed for each case
Gross description
  • 1 - 6 cm grossly cystic lesion arising within paratestis / testis
  • Cyst wall is variably thickened with protrusions
  • Papillae may be visualized focally but usually are not a prominent feature
Microscopic (histologic) description
  • Histologically identical to their ovarian counterpart
  • Tumors are cystic with numerous intracystic blunt papillae lined by ciliated stratified columnar cells with minimal to mild cytologic atypia
  • Psammoma bodies may be present
  • Cyst wall shows variable amount of fibrous tissue
  • Ki67 staining index varies from 1% to 10%
Cytology description
  • Fluid smears with scattered epithelial cells
  • Occasional papillary frond may be visualized but is usually not a prominent feature
Positive stains
Negative stains
Molecular / cytogenetics description
  • No specific cytogenetic abnormality has been documented
Differential diagnosis
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