Soft Tissue
Other tumors
Epithelioid sarcoma

Author: David L. Stockman, M.D. (see Authors page)

Revised: 27 April 2016, last major update April 2016

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: Epithelioid sarcoma [title] soft tissue

Related topics: Cutaneous, Proximal type

Cite this page: Epithelioid sarcoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/softtissueepithelioidsarcoma.html. Accessed December 5th, 2016.
Definition / General
  • Uncommon, usually mass in subcutaneous to fascial based soft tissue sites of distal extremities of young adults
  • Cases are often missed and excised with diagnoses of reactive conditions, but will recur
  • Metastases in 45% of cases, usually to lungs, other skin sites with proclivity for scalp, lymph nodes
  • Poor prognosis; death from disease in 31%
  • May have atypical biological behavior of tumor due to nodal metastases, size, unusual sites (Rom J Morphol Embryol 2005;46:229, JCAD Online 2009)
  • May derive from mesenchymal cells undergoing epithelial differentiation
Prognostic Factors
  • Poor prognostic factors: proximal/axial tumor, large size, deep tumor, hemorrhage, mitotic figures, necrosis, rhabdoid features, angiolymphatic invasion
Treatment
  • Wide local excision, lymph node dissection, radiation therapy
Clinical Images

Images hosted on Pathout server:
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Hand, courtesy of Dr. Mark R. Wick

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Heel, courtesy of Dr. Mark R. Wick

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Foot

Micro Description
  • Epithelioid tumor cells in granuloma-like fashion around areas of necrosis and central hyalinization
  • Striking acidophilic tissue due to cytoplasmic staining and desmoplasia
  • Tumor usually in reticular dermis, sometimes deeper soft tissue around fascial plans, aponeuroses, tendon sheaths
Micro Images

Images hosted on Pathout server:

Images courtesy of Dr. Mark R. Wick

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Various images


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Various images

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Nerve invasion


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EMA

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INI1

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Pankeratin




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Site unknown

Forearm


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Cyclin D1+

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keratin+, IN1-

Rhabdoid cells



Positive Stains
Negative Stains
Electron Microscopy Description
  • Abundant intermediate filaments, desmosome-like junctions, small intercellular spaces with microvilli
Molecular / Cytogenetics Description
Differential Diagnosis