Other mesenchymal tumors
Undifferentiated uterine sarcoma

Topic Completed: 1 September 2011

Minor changes: 12 August 2020

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PubMed search: undifferentiated uterine sarcoma

Mohamed Mokhtar Desouki, M.D., Ph.D.
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Cite this page: Desouki M. Undifferentiated uterine sarcoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/uterussarcoma.html. Accessed April 18th, 2021.
Definition / general
  • Rare tumors that display pleomorphic cells with high mitotic index that show no evidence of stromal or smooth muscle derivation
  • Considered to be variants of MMMT, but without an epithelial component and lacking endometrial stromal features
  • Must sample thoroughly to rule out MMMT
  • Poor prognosis
  • Undifferentiated uterine or endometrial sarcoma
  • Average age 45 years, present with vaginal bleeding
Case reports
  • No consistent data available
Gross description
  • Necrotic fleshy, bulky tumor fills uterine cavity with polypoid appearance usually with deep myometrial invasion
Microscopic (histologic) description
  • Marked nuclear anaplasia, variable pleomorphism, 20+ mitotic figures/10 HPF
  • Large round, spindle or bizarre cells; chromatin is coarse, clumped with large prominent nucleoli
  • Extensive necrosis is a common feature
  • Entrapped glands usually small, inconspicuous, not surrounded by condensed stroma as in adenosarcoma
Microscopic (histologic) images

AFIP images

Undifferentiated sar-
coma of endometrium -
pleomorphic giant and
spindle cells

Undifferentiated sarcoma of endo-
metrium - poorly differentiated
spindled cells, numerous mitoses,
necrosis at lower right

Negative stains
Differential diagnosis
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