Skip to Main Content


Tumor is a descriptive term for a growth or mass of cells that are independent of the physiologic function or demand of their surrounding structures. The two characteristic biological growth patterns of tumors include the ability to (1) disrespect tissue boundaries and invade other structures (invasiveness) and (2) gain access to blood and lymph vessels or other structures to spread tumor cells to distant locations, and allow these specially equipped cells to survive and grow new remote tumors (metastases). If a tumor does not have either property, it is benign; if a tumor can invade locally but even at a large size does not have a tendency to metastasize, it is called semimalignant; and if a tumor has the ability to metastasize once a sufficient size is reached, it is a malignant tumor.


Colorectal lesions may be classified as either benign, potentially malignant, or malignant based on their pathological features (Table 36–1); the semimalignant variant with invasion only but no affinity to later form of metastases is not common in the colon. The overwhelming majority of colorectal tumors are of epithelial origin and arise from the mucosal surface, where they become visible descriptively as a polyp. Benign polyps include nonneoplastic polyps (eg, hyperplastic, hamartomatous, or inflammatory polyps); the potentially malignant group consists of adenomatous polyps. Once dysplastic cells in a polyp cross the boundaries of the mucosa (basement membrane and muscularis mucosae) and start to invade the submucosa and the muscularis mucosae, a true cancer (carcinoma) with the potential to metastasize is established. Tumors of nonepithelial or mesenchymal origin are comparably rare and include, among others, lipoma, lymphoma, carcinoid, and sarcoma.1–3

Table Graphic Jump Location
Table 36-1: Introduction: Classification of Colon Tumors

Colonic tumors are important for two reasons: First, they are frequent and account for both a significant mortality rate as well as high cumulative health care costs. Second, the ...

Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.


About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessSurgery Full Site: One-Year Subscription

Connect to the full suite of AccessSurgery content and resources including more than 160 instructional videos, 16,000+ high-quality images, interactive board review, 20+ textbooks, and more.

$995 USD
Buy Now

Pay Per View: Timed Access to all of AccessSurgery

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.