Mesenchymal tumors


Topic Completed: 17 February 2021

Minor changes: 3 March 2021

Copyright: 2003-2021,, Inc.

PubMed search: colonic schwannoma

Raul S. Gonzalez, M.D.
Page views in 2020: 1,414
Page views in 2021 to date: 1,663
Cite this page: Gonzalez RS. Schwannoma. website. Accessed October 24th, 2021.
Definition / general
  • Uncommon mesenchymal tumor of colon
Essential features
  • Benign spindle cell lesion of muscularis propria with prominent lymphoid cuff
  • Positive for S100, unlike gastrointestinal stromal tumor (GIST)
  • No syndromic association
  • GANT is an outdated term for GIST, not schwannoma
  • Rare; less common than colonic GIST
  • Colon is second most common site in gastrointestinal tract for schwannoma, after stomach
Clinical features
Case reports
Clinical images

Images hosted on other servers:

Submucosal colonic tumors

Gross description
  • Well circumscribed but usually not encapsulated
  • Polypoid intraluminal mass with mucosal ulceration, usually in right colon
Gross images

Images hosted on other servers:

Various images

Microscopic (histologic) description
  • Nonencapsulated, polypoid lesion arising in muscularis propria (Mod Pathol 2015;28:S47)
  • Bland spindle cells with elongated, pointed nuclei; no or indistinct Verocay bodies and no prominent nuclear palisading
  • Stroma may be myxoid and contain prominent collagen bands
  • Surrounded by lymphoid cuff
  • May have microcystic or reticular features or may be epithelioid (Am J Surg Pathol 2008;32:1080)
  • May have focal nuclear atypia; mitotic figures rare
  • Usually no vascular hyalinization or xanthoma cells
Microscopic (histologic) images

Contributed by Raul S. Gonzalez, M.D.


Images hosted on other servers:

Various images

Various immunostains

Positive stains
Negative stains
Sample pathology report
  • Rectosigmoid colon, resection:
    • Schwannoma (4.1 cm) (see comment)
    • Margins of resection unremarkable.
    • Three benign lymph nodes.
    • Comment: An immunohistochemical stain for S100 is positive.
Differential diagnosis
Board review style question #1
Which of the following is a common feature of gastrointestinal schwannomas?

  1. Artifactual cytoplasmic vacuoles
  2. Dense cellularity and high mitotic rate
  3. Epicenter in the muscularis mucosae
  4. Peripheral lymphoid cuff
  5. Verocay bodies and thick walled vasculature
Board review style answer #1
D. Peripheral lymphoid cuff

Comment here

Reference: Schwannoma
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