Testis & epididymis
Germ cell tumors

Topic Completed: 1 February 2014

Minor changes: 10 September 2020

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PubMed Search: Osteosarcoma [title] testis

Jennifer Gordetsky, M.D.
Page views in 2020: 164
Page views in 2021 to date: 9
Cite this page: Gordetsky J. Osteosarcoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/testisosteosarcoma.html. Accessed January 17th, 2021.
Definition / general
  • A testicular tumor composed of pure osteoid forming malignant cells with no skeletal origin
  • Pure testicular osteosarcoma is exceptionally rare
  • Case reports: mean 59 years, range 30 - 78 years
  • Usually derive from sarcomatous transformation of germ cell tumors (teratoma)
  • May also occur as a component of malignant mixed sex cord / stromal tumor
  • Pure osteosarcomas without teratomatous elements have also been reported; may arise from primitive testicular stromal cells or metaplastic stromal cells (Virchows Arch 2004;445:210, Int J Urol 2006;13:323)
Clinical features
  • Scrotal mass
Radiology description
  • Intratesticular heterogeneous solid mass with focal calcification
Radiology images

Images hosted on other servers:

Left testicular mass almost entirely calcified

Prognostic factors
  • Organ confined disease is associated with a favorable prognosis
Case reports
  • Orchiectomy
Gross description
  • Well circumscribed, solid, firm, whitish tan, expansile mass compressing the surrounding testicular parenchyma
Gross images

Images hosted on other servers:

Off white colored tumor

Microscopic (histologic) description
  • Sheets of pleomorphic round to spindled cells with prominent nucleoli
  • Areas of neoplastic osteoid with scattered foci of mineralization
  • High mitotic activity and atypical mitoses
  • Osteoclasts can be seen among the area of osteoid formation
Microscopic (histologic) images

Images hosted on other servers:

Sarcomatous cell proliferation - H&E

Molecular / cytogenetics description
Differential diagnosis
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