Colon tumor
Mesenchymal tumors

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

Revised: 4 January 2017, last major update June 2016

Copyright: (c) 2003-2017,, Inc.

PubMed Search: Colon tumor perineurioma
Cite this page: Perineurioma. website. Accessed June 19th, 2018.
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

Images hosted on Pathout server:

Contributed by: Raul S. Gonzalez, M.D., University of Rochester Medical Center (USA)

Images hosted on other servers:
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H&E showing uniform spindle cells

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H&E demonstrating
epithelial and mesenchymal

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Perineal tumor:
H&E and EMA

Positive stains
Electron microscopy description
  • Long bipolar cytoplasmic processes, prominent pinocytotic vesicles
Molecular / cytogenetics description
Differential diagnosis