Mesenchymal tumors


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Last staff update: 5 February 2021

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PubMed Search: Colon perineurioma [title]

Raul S. Gonzalez, M.D.
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Cite this page: Gonzalez RS. Perineurioma. website. Accessed April 1st, 2023.
Definition / general
  • Benign polypoid lesion occurring in the colonic mucosa or submucosa
  • Peripheral nerve sheath tumor, often with overlying serrated / hyperplastic epithelium
Essential features
  • Uncommon mucosal epithelial-mesenchymal lesion of the colon
  • Usually occurs in middle aged women
  • Benign, does not recur
  • Usually in distal colon; rarely in small intestine
Clinical features
  • Excision (benign behavior)
Gross description
  • Small sessile polyp (median size 0.4 cm)
Microscopic (histologic) description
  • Poorly circumscribed spindle cell proliferation, usually confined to the mucosa, with ovoid nuclei and pale indistinct cytoplasm, in a background of fine collagenous stroma
  • No atypia, no pleomorphism, no mitotic figures
  • Entrapped / overlying colonic crypts appear hyperplastic or serrated in the majority of cases
  • Perineurial proliferation sometimes focally present in otherwise typical sessile serrated polyp / adenoma (Am J Surg Pathol 2011;35:1373)
Microscopic (histologic) images

Contributed by Raul S. Gonzalez, M.D. and Christopher Hartley, M.D.

Medium power

High power

Weak positivity on EMA


Positive stains
Electron microscopy description
  • Long bipolar cytoplasmic processes, prominent pinocytotic vesicles
Molecular / cytogenetics description
Sample pathology report
  • Ascending colon, polypectomy:
    • Perineurioma (see comment)
    • Comment: Immunohistochemical stains show the lesion is positive for EMA (focal) and negative for S100.
Differential diagnosis
Board review style question #1

Colonic perineuriomas are positive for which of the following immunohistochemical stains?

  1. CD117
  2. Claudin1
  3. Desmin
  4. S100
Board review style answer #1
B. Claudin1

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Reference: Perineurioma
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