A fibroepithelial polyp, better known as an acrochordon and also referred to as a skin tag, is a soft, tiny benign tumor that appears on the skin. It is usually formed where the skin creates creases or folds. The two most common areas of occurrence are the armpit and neck, while other areas include the eyelids, buttocks folds, groin and chest, especially underneath the breasts of women.
The fibroepithelial polyp derived its name from the specific location of development, the epithelium. One of the major types of tissue in the body, it is responsible for covering the body's internal surface. The skin tags usually have the size and shape of a grain of rice, although there are instances of polyps being a little longer, at up to 0.5 inches (12.7 mm).
It is commonly thought these polyps are formed due to contact of skin regions with one another. This is given as the reason why the skin tags are most likely to occur at skin creases and folds. Lending credence to that theory is the disproportionate occurrence of fibroepithelial polyps in overweight or obese people, who have more folds of fat than do people of average weight. There is no substantial explanation, however, for why skin tags are also more likely to occur among middle-aged and elderly people as well as in people who have diabetes. Some medical researchers have pointed to the possibility of genetic disorders such as cyst-causing Birt–Hogg–Dubé syndrome as a contributing factor.
The fibroepithelial polyp is generally harmless, and it does not cause pain or discomfort. There is always the possibility, however, that it might be precancerous or develop into skin cancer. There is also the aesthetic factor to consider; while some people are rather tolerant of the skin tags, others might worry about how they are adversely affecting their looks. Physicians can remove the polyps by slicing them off with scissors, burning them off with electric cautery, or freezing them with liquid nitrogen.
Some fibroepithelial polyps may acquire a purple or black color. This indicates that the skin tag has developed a blood clot, or thrombus. Usually, thrombosed skin tags, like any other polyp, are harmless, and they can fall off within three to 10 days after the blood coagulation occurs. Concerned patients, however, may want to visit their physicians to ensure that the skin tags are not an indication of skin cancer.