Keloids are smooth, shiny, flesh-colored, raised growths of fibrous tissue that form over areas of injury or surgical wounds.
Keloids are an extreme overgrowth of scar tissue over healed wounds. They may form in the months after an injury. They may be raised as much as ¼ inch above the surface of the skin. Keloids may form in any scar, even those resulting from severe acne. They are much more common in blacks than in whites and typically develop on the chest, shoulders, back, and, sometimes, face and earlobes. Keloids do not hurt, but they may itch or be sensitive to touch.
Keloids respond poorly to therapy, but monthly injections of corticosteroids may flatten them somewhat. A doctor may try surgical or laser removal followed by corticosteroid injections, but new keloids often form in the scar resulting from the treatment. Some doctors have applied silicone patches to keloids and have had some success in flattening them.
Keratoacanthomas are round, firm, usually flesh-colored growths that have a central crater that is scaly or crusted.
Keratoacanthomas appear most commonly on the face, forearm, and back of the hand and grow quickly. In 1 or 2 months, they can grow into lumps up to 1 inch wide, after which they begin to shrink. They usually disappear within 6 months, often leaving a scar. They may be caused by a virus, but doctors are not sure.
Keratoacanthomas closely resemble squamous cell carcinoma, a type of skin cancer, and some doctors believe that they may actually be an unusual form of squamous cell carcinoma. Therefore, doctors often perform a biopsy, in which a piece of skin is removed and examined under a microscope. Keratoacanthomas can be cut out or scraped (curetted). Alternatively, they can be treated with injections of corticosteroids or fluorouracil
Lipomas are soft deposits of fatty material that grow under the skin, causing round or oval lumps.
A lipoma appears as a smooth, soft bump under the skin. Lipomas range in firmness, some feeling rather hard. The skin over the lipoma has a normal appearance. Lipomas rarely grow more than 2 or 3 inches across. They can develop anywhere on the body but are particularly common on the forearms, torso, and back of the neck. Some people have only one, whereas others develop many lipomas. Lipomas rarely cause problems, although they may occasionally be painful if they grow against a nerve. Lipomas are more common in women than in men.
Usually, a doctor can easily recognize lipomas, and no tests are required for diagnosis. Lipomas are not a form of cancer, and they rarely become cancerous. If a lipoma begins to change in any way, a doctor may perform a biopsy (removal of a tissue sample for examination under a microscope). Treatment usually is not required, but bothersome lipomas may be removed by surgery or by liposuction (removal of fat with a suction device).
Moles (nevi) are small, usually dark, skin growths that develop from pigment-producing cells in the skin (melanocytes).
Moles vary in size from small dots to more than 1 inch in diameter. They may be flat or raised, smooth or rough (wartlike), and may have hairs growing from them. Although they are usually dark brown or black, some moles are flesh-colored or yellow-brown. They may be red at first but often darken. Almost everyone has a few moles, and many people have large numbers of moles. Moles commonly develop in childhood or adolescence, although in some people they continue to develop throughout life. Moles respond to changes in hormone levels in women and may appear, enlarge, or darken during pregnancy. Once formed, moles remain for a lifetime. In fair-skinned people, moles occur more commonly on sun-exposed areas of the skin.
Moles usually are easily recognized by their typical appearance. They do not itch or hurt, and they are not a form of cancer. However, moles sometimes develop into or resemble malignant melanoma, a cancerous growth of melanocytes. In fact, many malignant melanomas begin in moles, so a mole that looks suspicious should be removed and examined under a microscope. Changes in a mole—such as enlargement (especially with an irregular border), darkening, inflammation, spotty color changes, bleeding, broken skin, itching, or pain—are warnings of malignant melanoma. People with more than 10 or 20 moles have a somewhat increased risk of melanoma and should be checked every year by a doctor. If a mole proves to be cancerous, additional surgery may be needed to remove the skin surrounding it.
Most moles, however, are harmless and do not require removal. Depending on their appearance and location, some moles may even be considered beauty marks. Normal moles that are unattractive or located where clothing can irritate them can be removed by a doctor using a scalpel and a local anesthetic.
Atypical moles (dysplastic nevi) tend to be larger than normal moles. Like cancerous skin growths, they tend to be multicolored and have irregular shapes and borders. People with even a few atypical moles have a slightly increased risk of developing malignant melanoma. This risk increases greatly if the person has close family members with malignant melanoma. The tendency to grow atypical moles is hereditary.
People with atypical moles—particularly those with a family history of melanoma—must look for any changes that might indicate malignant melanoma. They should have their skin checked at least yearly by a dermatologist to look for changes in the color or size of a mole. To help monitor such changes, dermatologists often use full-body color photographs. Atypical moles that change should be removed.
Sunlight accelerates the development of and changes in atypical moles. Even moderate sun exposure during childhood may be harmful and increase the risk of developing melanoma decades later. Therefore, fair-skinned people or those with atypical moles should avoid sun exposure. When in the sun, they should always use a sunblock with a high sun protection factor (SPF) rating to help shield against cancer-producing ultraviolet (UV) rays.
Adapted from: Merck & Co. Inc
March 30, 2007
Keloids, Keratoacanthomas, Lipomas, Moles