[Colorectal polyps].
The polyp is a focal mass that projects from the wall into the lumen. The term polyp is appropriate for gross, radiologic, and endoscopic usage and should be further modified to indicate topographic site, size, number and shape. Strictly spoken, a polyp consists of a head and a stalk, but also the lesions without a clear stalk, but still protruding into the lumen, are called (sessile) polyps. In this view, "polyp" means any lesion, which is circumscribed and raised above normal surrounding mucous membrane so that it is visible to the naked eye. Clinicians sometimes even use "polyp" to refer to any tumor detected in the large intestine. The term polyp does not hold any information about the pathological nature of the lesions. Some polyps (benign, non-neoplastic polyps) do not have an increased potential for becoming malignant, while other polyps (adenomas, neoplastic polyps) are precancerous, which may progress to malignant lesions (carcinomas). Thus polyps must be biopsied or resected to determine their histological type and establish a complete diagnosis.