The word polyp refers to any overgrowth of tissue from the surface of mucous membranes. Polyps come in a variety of shapes--round, droplet, and irregular being the most common; and they affect various parts of the body--the intestines, the nasal passages, the rectum, and the vocal cords.

Polyps are one of many forms of tissue overproduction that can occur in the body. Cells in many body tissues sometimes keep growing beyond their usual limits. Medical scientists call this process neoplasia, which means simply "new growth." An individual overgrowth is called a neoplasm. In most cases these growths are limited, and the result is a benign swelling or mass of cells called a tumor. If the new growth occurs on the surface of the tissue instead of inside an organ it is often called a polyp. Cancer is another type of neoplasm marked by unlimited tissue growth. The essential...