Uterus
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
Table of Contents
Definition / general | Terminology | Epidemiology | Case reports | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Negative stains | Differential diagnosisCite this page: Desouki M. Undifferentiated uterine sarcoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/uterussarcoma.html. Accessed January 24th, 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
Terminology
- Undifferentiated uterine or endometrial sarcoma
Epidemiology
- Average age 45 years, present with vaginal bleeding
Case reports
- 80 year old woman presenting with pathologic fracture of humerus (Mil Med 2010;175:691)
Treatment
- 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
- Endometrial stromal sarcoma: high grade tumors resemble stromal component of MMMT
- Leiomyosarcoma: spindle cells resemble smooth muscle with moderate to severe pleomorphism
- Rhadbdomyosarcoma
