Colon, Invasive adenocarcinoma in adenomatous polyp

Details
Disease Category
Gender
Age
70 years
Organ System/Discipline
Diagnosis
Invasive adenocarcinoma in adenomatous polyp
Clinical History

Sigmoid colon lesion.

Case Discussion

One of the major aims of endoscopic screening programs is the identification and resection of adenomatous polyps from the colorectum, as these lesions are considered to be pre-malignant and will eventually develop into invasive adenocarcinoma if allowed to grow over a period of time. Adenomata by definition are abnormal proliferations of gland-forming epithelium which shows low grade dysplasia, and their presence warrants more frequent screening in the future for patients who have them. Other features, such as large size (>1.0cm), presence of a villous component, high grade dysplasia, and greater than 3 polyps, warrants even more frequent follow up.

In this case, we see an example of an adenomatous polyp showing both tubular and villous architectural patterns of growth, and is thus classified as a tubulovillous adenoma. There is, however, also a component of this polyp which shows dysplastic glands with a haphazard pattern of growth infiltrating beyond the muscularis mucosae. This component of the lesion is a frank invasive carcinoma, which must be brought to the attention of the managing team so that adequate resection of the lesion can be achieved.

Image Contributors
Shivji, S., Latta, E.

Cite

Shivji, S., Latta, E. Colon, Invasive adenocarcinoma in adenomatous polyp. Digital Laboratory Medicine Library, Dept of Laboratory Medicine & Pathobiology, University of Toronto. Published . Accessed December 17, 2025. https://dev.dlml.cflabs.ca/image/colon-invasive-adenocarcinoma-adenomatous-polyp-lmp88608