Colon tumor
Mesenchymal tumors
Histiocytic sarcoma of colon

Topic Completed: 1 November 2016

Revised: 9 July 2019

Copyright: 2003-2019,, Inc.

PubMed Search: histiocytic sarcoma colon

Raul S. Gonzalez, M.D.
Page views in 2019: 725
Page views in 2020 to date: 164
Cite this page: Gonzalez R. Histiocytic sarcoma of colon. website. Accessed March 31st, 2020.
Definition / general
Essential features
  • Rare primary sarcoma of the gastrointestinal tract featuring CD163 positivity
  • Can be mistaken for lymphoma with infiltrating histiocytes
  • Previously also called "true histiocytic lymphoma"
  • Gastrointestinal tract most common location, after skin / soft tissue
  • Colonic examples are often distal (sigmoid / rectum)
Clinical features
  • Median age 55 years, with no sex predilection (Am J Surg Pathol 2004;28:1133)
  • Symptoms include weight loss, abdominal pain and hematochezia
  • Postoperative outcome can vary from full recovery to death
Gross description
  • Bulky exophytic mass with infiltrative margins
Microscopic (histologic) description
  • Sheets of large epithelioid cells with abundant eosinophilic cytoplasm, oval to irregular nuclei, vesicular chromatin, prominent nucleoli and distinct borders; cells may be binucleated, giant or spindled
  • Prominent inflammatory infiltrate (lymphocytes, eosinophils, neutrophils)
  • Often mitotic activity and necrosis
  • Regional lymph nodes generally involved
Microscopic (histologic) images
Contributed by Raul Gonzalez, M.D.

Low power

Abundant lymphocytes

High power

Multinucleated cells

Positive stains
Electron microscopy description
  • Cells contain scattered lysosomes, consistent with histiocytic origin
Molecular / cytogenetics description
  • May show monoclonal IgH bands or IgH and TCR gamma gene rearrangements
Differential diagnosis
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