Colon tumor
Small cell carcinoma of colon

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

Revised: 5 January 2016, last major update October 2015

Copyright: (c) 2002-2016,, Inc.

PubMed Search: Small cell carcinoma [title] colon
Cite this page: Small cell carcinoma of colon. website. Accessed October 24th, 2016.
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

Micro 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
Micro 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