Anus & perianal

Topic Completed: 1 November 2014

Minor changes: 20 August 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Carcinosarcoma anal

Raul S. Gonzalez, M.D.
Page views in 2019: 487
Page views in 2020 to date: 311
Cite this page: Gonzalez RS. Carcinosarcoma. website. Accessed May 24th, 2020.
Definition / general
  • Rare anal malignancy with areas of true epithelial differentiation and separate areas of true mesenchymal differentiation
  • "Carcinosarcoma" has been used interchangeably with "sarcomatoid carcinoma" though the latter term implies lack of true sarcomatous differentiation (Pathology 2006;38:264)
  • Extremely rare
Case reports
Microscopic (histologic) description
  • Epithelial component is usually squamous cell carcinoma; mesenchymal component appears spindled or undifferentiated and cannot necessarily be categorized; the two components may be intimately admixed
Positive stains
  • Keratin (in epithelial component only); vimentin (in mesenchymal component)
Differential diagnosis
  • Sarcomatoid carcinoma: epithelial tumor with areas of spindle cell morphology, resembling a sarcomatoid component but without true sarcomatoid differentiation
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