Colon tumor
Invasive carcinoma arising in a colonic adenoma

Topic Completed: 1 September 2010

Minor changes: 10 June 2019

Copyright: 2003-2018,, Inc.

PubMed Search: Invasive carcinoma arising colonic adenoma

Shilpa Jain, M.D.
Page views in 2019: 2,213
Page views in 2020 to date: 779
Cite this page: Jain S. Invasive carcinoma arising in a colonic adenoma. website. Accessed May 30th, 2020.
Definition / general
  • Invasive only if cancer has invaded beyond muscularis mucosa into submucosa
  • Can diagnose invasion without identification of submucosa if (a) marked desmoplasia, (b) infiltrative pattern, (c) ulceration or (d) clinical mass lesion
  • Recommended to NOT use "carcinoma in situ" terminology in colorectum; use either high grade dysplasia or invasive carcinoma
Prognostic factors
  • Recurrent disease, nodal metastases or residual local disease: 20% incidence if cancer is near margin, is poorly differentiated or if angiolymphatic invasion is present
Case reports
Microscopic (histologic) description
  • How to Report:
    • Report type of carcinoma, grade, presence of angiolymphatic invasion (tumor emboli in true endothelial lined channels away from tumor, not retraction artifact), status of resection margins (close to margin is within one high power field or 1-2 mm from diathermy or at diathermy), presence of dysplasia
    • Sample report #1: poorly differentiated carcinoma arising within an adenoma, extending to resection margin, no angiolymphatic invasion
    • Sample report #2: moderately differentiated carcinoma arising with an adenoma; tumor 2.5 cm from resection margin, no angiolymphatic invasion
Microscopic (histologic) images

Images hosted on other servers:

Arising in villous adenoma

Metastatic signet ring cell adenocarcinoma in adenoma

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