Colon
Other tumors
Metastases


Topic Completed: 1 February 2021

Minor changes: 1 February 2021

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PubMed Search: Metastases [title] colon

Raul S. Gonzalez, M.D.
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Cite this page: Gonzalez RS. Metastases. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/colontumormetastases.html. Accessed April 19th, 2021.
Definition / general
  • Secondary involvement of colon by a neoplasm of extracolonic origin
  • Uncommon (for example, occurs in 2% of breast and lung carcinomas)
Essential features
  • Metastases more common in small intestine than in colon
  • Primary lesion is often but not always identifiable
  • Most common primaries are stomach, lung, prostate, breast and ovarian carcinomas and melanoma
Clinical features
  • Endometrioid adenocarcinoma: if associated with colonic endometriosis, then represents an enigmatic primary rather than a metastasis
  • Leukemia: usually involves right colon and terminal ileum, as polypoid or transmural infiltrates
  • Melanoma: may have long interval between primary lesion and metastases (Dis Colon Rectum 2003;46:441)
  • Prostate: more common to be direct spread / invasion than a metastasis
    • Resections for rectal cancer may rarely contain lymph nodes with metastatic prostate carcinoma
Clinical images

Images hosted on other servers:
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Soft tissue mass
due to squamous
cell carcinoma
primary of lung

Case reports
Gross description
  • Central ulceration extending toward mucosa but often sparing it
Microscopic (histologic) description
  • Disease usually resembles primary tumor microscopically
  • Metastases may be present along serosal surface or within the wall but mucosal involvement is uncommon
  • Adjacent / overlying colonic epithelium is not dysplastic
Microscopic (histologic) images

Contributed by Raul S. Gonzalez, M.D.

Metastatic breast carcinoma

Metastatic ovarian clear cell carcinoma



Images hosted on other servers:
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Metastatic melaonoma to sigmoid colon

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Poorly differentiated
squamous cell
carcinoma metastatic
from lung

Sample pathology report
  • Descending colon, resection:
    • Segment of colon with multiple serosal foci of metastatic high grade serous carcinoma, consistent with known ovarian primary
    • Margins of resection unremarkable.
    • Eight lymph nodes, negative for malignancy (0/8).
Differential diagnosis
Board review style question #1
While metastases to the colon are rare, some diseases metastasize there more often than others. Which of the following malignancies metastasizes to the colon relatively frequently?

  1. Melanoma
  2. Salivary gland carcinoma
  3. Synovial sarcoma
  4. Urothelial carcinoma
Board review style answer #1
A. Melanoma

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