Difference between revisions of "Pleomorphic undifferentiated sarcoma"
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'''Pleomorphic undifferentiated sarcoma''', abbreviated '''PUS''', is an undifferentiated malignant [[soft tissue lesion]]. | |||
It is also known as '''undifferentiated pleomorphic sarcoma''' (abbreviated '''UPS'''). Previously, it was known as '''malignant fibrous histiocytoma''', commonly abbreviated '''MFH'''.<ref>URL: [http://sarcomahelp.org/learning_center/mfh.html http://sarcomahelp.org/learning_center/mfh.html]. Accessed on: 8 April 2011.</ref> | |||
==General== | |||
*Common sarcoma. | |||
*Usually deep tissue of the trunk and extremities. | |||
*A diagnosis of exclusion<ref name=pmid19671033>{{cite journal |author=Matushansky I, Charytonowicz E, Mills J, Siddiqi S, Hricik T, Cordon-Cardo C |title=MFH classification: differentiating undifferentiated pleomorphic sarcoma in the 21st Century |journal=Expert Rev Anticancer Ther |volume=9 |issue=8 |pages=1135–44 |year=2009 |month=August |pmid=19671033 |pmc=3000413 |doi=10.1586/era.09.76 |url=}}</ref> / wastebasket for unclassifiable high grade sarcomas. | |||
==Microscopic== | |||
Features:<ref name=Ref_WMSP_613>{{Ref WMSP|613}}</ref> | |||
*Storiform pattern ([[AKA]] ''patternless pattern'') - '''key feature'''. | |||
*Marked [[nuclear pleomorphism]] '''key feature'''. | |||
**Variation is nuclear size, nuclear shape and nuclear staining (esp. hyperchromasia). | |||
*Mitoses - abundant; atypical mitoses common. | |||
*Necrosis (common). | |||
*Mix of spindle cells and epithelioid cells. | |||
*Deep to skin - '''important'''. | |||
Other findings: | |||
*+/-Giant cells (see subclassification). | |||
*+/-Inflammation (see subclassification). | |||
**Neutrophils. | |||
**Eosinophils. | |||
Notes: | |||
*Superficial lesions with the morphology of ''PUS'' are called by some ''[[atypical fibroxanthoma]]s'' (AFXs). | |||
DDx: | |||
*[[Atypical fibroxanthoma]] (AFX) - superficial skin. | |||
*[[Dedifferentiated liposarcoma]]. | |||
*[[Leiomyosarcoma]]. | |||
*[[Metaplastic carcinoma]]. | |||
*[[Malignant melanoma]]. | |||
*[[Rhabdomyosarcoma]]. | |||
*[[Synovial sarcoma]]. | |||
*[[Undifferentiated endometrial sarcoma]] - uterus. | |||
*Others. | |||
===Images=== | |||
<gallery> | |||
Image:Pleomorphic_undifferentiated_sarcoma_-_very_high_mag.jpg | PUS - high mag. (WC/Nephron) | |||
Image:Pleomorphic_undifferentiated_sarcoma_-_intermed_mag.jpg | PUS - intermed. mag. (WC/Nephron) | |||
</gallery> | |||
===Subclassification=== | |||
Pleomorphic sarcoma (PS) is subclassified the following way:<ref name=Ref_WMSP_613-4>{{Ref WMSP|613-4}}</ref> | |||
*PS with giant cells. | |||
*PS with inflammation. | |||
*PUS (not otherwise specified) - wastebasket diagnosis; if neither of the above two apply. | |||
==IHC== | |||
Exclusionary stains - should be negative: | |||
*AE1/AE3. | |||
*p63. | |||
*Myogenin. | |||
*S-100. | |||
*HMB-45. | |||
Usually negative, may be positive:<ref name=Ref_WMSP613>{{Ref WMSP|613}}</ref> | |||
*Desmin. | |||
*SMA. | |||
Commonly positive: | |||
*CD68.<ref name=Ref_WMSP613>{{Ref WMSP|613}}</ref> | |||
*Vimentin. | |||
==See also== | |||
*[[Sarcoma]]. | |||
==References== | |||
{{Reflist|2}} | |||
[[Category:Diagnosis]] | [[Category:Diagnosis]] | ||
[[Category:Soft tissue lesions]] | |||