Intramucosal colorectal carcinoma

The layers of the GI tract from inside (mucosa) to outside (serosa/adventitia). (WC)

Intramucosal colorectal carcinoma is a confusing term for high grade (colorectal) dysplasia that should be avoided.

Intramucosal rectal carcinoma, intramucosal colonic carcinoma, intramucosal colonic adenocarcinoma, intramucosal rectal adenocarcinoma, intramucosal adenocarcinoma of the colon‎, and colorectal adenocarcinoma in situ redirect here.

Background

• Colorectal adenocarcinoma is defined by invasion into the submucosa.
  • This is different than elsewhere in the GI tract, where cancer is defined by invasion through the basement membrane, i.e. into the lamina propria.
  • Rationale: atypical (cancer-like) cells in lamina propria do not have metastatic potential as there are no lymphatics in the colorectal lamina propria.

Note:

• If one wants to differentiate adenocarcinoma in situ and high-grade dysplasia:
  • Adenocarcinoma in situ has invasion into the lamina propria and high-grade dysplasia does not have lamina propria invasion. Thus, the difference amounts to seeing a desmoplastic stroma or infiltrative cells; if one of these is present it is adenocarcinoma in situ, if both are not it is dysplasia.

See also

• Colorectal adenocarcinoma.
• Traditional adenoma.
• Intramucosal carcinoma.
• Colorectal cancer staging.
• Pseudoinvasion.