Anus and perianal area

Author: Raul Gonzalez, M.D. (see Authors page)

Revised: 9 October 2017, last major update November 2014

Copyright: (c) 2002-2017,, Inc.

PubMed Search: Carcinosarcoma anal

Page views in 2017: 93
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Cite this page: Gonzalez, R. Carcinosarcoma. website. Accessed December 18th, 2018.
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