Testis and epididymis
Paratesticular tumors
Well differentiated papillary mesothelioma

Author: Jennifer Gordetsky, M.D. (see Authors page)

Revised: 2 June 2017, last major update November 2013

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PubMed Search: Benign mesothelioma [title] testis

Related topics: Malignant mesothelioma
Cite this page: Well differentiated papillary mesothelioma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/testismesothelioma.html. Accessed August 15th, 2018.
Definition / general
  • A rare benign tumor of mesothelial origin
  • Usually occurs in the peritoneum of young women
  • Few cases reported in the tunica vaginalis of the testis
  • Ages ranging from 18 to 69
  • Peritoneum and tunica vaginalis
Clinical features
  • Scrotal / peritesticular mass, associated with hydrocele
  • Mesothelial origin can be confirmed by immunohistochemical stains
Case reports
  • Complete excision
Microscopic (histologic) images

Images hosted on other servers:

Typical tubulopapillary pattern

Psammoma body in papillary area

Papillary tumor

Immunohistochemical staining

Cytology description
  • Moderately cellular, uniform epithelioid cells arranged in papillary groups with fibrovascular cores
  • Cells have moderate cytoplasm, uniform round nuclei, distinct nucleoli
  • Minimal atypia
  • Few lymphocytes scattered in the background
  • No mitoses
Negative stains
  • p53 (may have focal positivity), CEA
Electron microscopy description
  • Tumor cells are round to polygonal in shape with numerous short and long slender microvilli on the free surfaces
  • Cytoplasmic organelles include moderate amounts of mitochondria, moderate amounts of rough endoplasmic reticulum, free ribosomes and microfilaments
  • Centrally located oval nuclei, euchromatin and prominent nucleoli
  • Well developed desmosomes (Pathol Res Pract 2010;206:105)