Colorectal tumours

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Colorectal tumours are very common. They are the bread and butter of GI pathology. Non-tumour colon is dealt with in the colon article.

An introduction to gastrointestinal pathology is in the gastrointestinal pathology article.

Classification

Other tumours - many (incomplete list):[2]

  • Mucinous carcinoma.
  • Adenosquamous carcinoma.
  • Signet-ring carcinoma.
  • Squamous carcinoma.
  • Neuroendocrine neoplasms (carcinoid tumours).
  • Lipoma.
  • Leiomyoma.
  • Gastrointestinal stromal tumour (GIST) - dealt with in a separate article.
  • Angiosarcoma.
  • Lymphoma (Non-Hodgkin's lymphoma).

Grading

  • "Adenocarcinoma in situ" and "high-grade dysplasia" is used interchangeably by many in the colon and rectum.
    • Splitting hairs - adenocarcinoma in situ is invasion into the lamina propria, high-grade dysplasia does not have lamina propria invasion. Ergo, the difference (in my opinion) amounts to seeing a desmoplastic stroma (adenocarcinoma) or not seeing one (dysplasia).

Grading of tumours:

  • Tis - in situ (intramucosal),
  • T1 - into submucosa (through mucularis mucosae),
    • this is different than elsewhere,
  • T2 - into muscularis propria,
  • T3 - into fat beyond musclaris propria,
  • T4 - into something else.

Nodes:

  • N0 - no positive nodes.
  • N1 - 1-3 positive nodes.
  • N2 - 4+ positive nodes.

Staging of colorectal cancer

Simple version

Tumour/node grade for stage:[3]

  • Stage I - T1 or T2 N0 M0.
  • Stage II - T3 or T4 N0 M0.
  • Stage III - Tx N1 or N2 M0.
  • Stage IV - Tx Nx M1.

Complex version

Detailed tumour/node grade for stage:[4]

  • Stage I - T1 or T2.
  • Stage IIA - T3.
  • Stage IIB - T4.
  • Stage IIIA - T1 N1 or T2 N1.
  • Stage IIIB - T3 N1 or T4 N1.
  • Stage IIIC - Tx N2.
  • Stage IV - Tx Nx M1.

See also

References