Colon tumor
Neuroendocrine neoplasms
Small cell carcinoma

Topic Completed: 1 October 2015

Revised: 13 September 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Small cell carcinoma [title] colon

Raul S. Gonzalez, M.D.
Page views in 2018: 1,130
Page views in 2019 to date: 953
Cite this page: Gonzalez R. Small cell carcinoma. website. Accessed September 17th, 2019.
Definition / general
  • One of two neuroendocrine carcinomas of the colon, along with large cell neuroendocrine carcinoma (discussed here)
  • Rare (< 1% of colorectal carcinomas) and aggressive (distant metastases common; 64% of patients dead at 5 months historically (Am J Clin Pathol 1991;95:315)
  • Usually in cecum or right colon, but can arise anywhere
Clinical features
  • Presents earlier than convention colorectal carcinoma (mean age ~ 60 years)
Prognostic factors
Case reports
Gross images

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Resected bowel

Microscopic (histologic) description
  • Resembles pulmonary small cell carcinoma
  • Sheets and nests of small ovoid cells with minimal cytoplasm, hyperchromatic nuclei with stippled chromatin, nuclear molding with peripheral palisading, brisk mitotic activity, apoptotic cells, necrosis and vascular invasion
  • May have Azzopardi effect (encrustation of nuclear material around blood vessels)
  • No prominent nucleoli or pleomorphism
Microscopic (histologic) images

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Mitoses, apoptosis and necrosis

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H&E and Synaptophysin

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Positive stains
Electron microscopy description
  • Dense core secretory granules
Differential diagnosis
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