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49 Colon: Carcinoma and polyp

Carcinoma of colon
Age/sex: 60-year-old male
Size: 30.2 x 10.3 x 6.3 cm
The specimen shows the sigmoid colon with a partly fungating (F) and partly ulcerated (U) carcinoma in its lower portion. Two polyps are evident. One overlies the carcinoma and is connected to the mucosa by a 2 ½ cm stalk (short arrow). The other (long arrow) appears to be sessile.


Carcinoma of colon

Carcinoma of the colon and rectum is one of the most frequent types of cancer, occurring in about 5% of Canadians. It is the most common cause of cancer death after cancers of the lung, breast, and prostate.

Most colon cancers are believed to begin as a benign polyp - a proliferation of mucosal epithelial cells that results in the formation of a small tumor elevated above the normal mucosa. Over time, genetic changes in some of the polyp’s cells as they divide may result in the development of malignancy. Surgically removed parts of the colon in people who have cancer often contain some polyps in addition to the main tumor. These observations are the basis for colonoscopy screening – to identify and remove any benign polyps before they can become malignant.

Symptoms of colon cancer include blood in the stool, constipation, and tiredness (particularly in cancers that occur in the right side of the colon). Although some cancers will have spread to adjacent lymph nodes or the liver at the time of diagnosis, the tumor is localized to the colon in many people, allowing potentially curative surgical resection.

Below: A round polyp can be seen attached by a stalk to the colonic wall (pedunculated polyp) on a double-contrast barium enema.

Source: Morgan, MA. (2023). Pedunculated tubulovillous adenoma. Radiopaedia.

A colon polyp on a stalk (known as a pedunculated polyp) seen on a double-contrast barium enema.

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