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Moles: Signs of Melanoma and Removal

Almost everybody has at least a few moles. Moles are made up of a collection of pigment cells and can be both, flat or raised on the skin. They can be found virtually anywhere on the body. Moles are more common in individuals who are exposed to a lot of sunshine but some are also present at birth, while others appear during childhood and adulthood. Some people have a genetic predisposition to develop lots of moles.

Up to one in fifty babies are born with a mole. Most of these are less than one centimetre (half an inch) in diameter but they can also be much larger. These large moles are known as giant moles or garment congenital melanocytic naevi.

Most moles are usually nothing to worry about. Despite that people should check them regularly and watch them for any signs of change because a very small amount may develop into a serious skin cancer.

Signs and Symptoms of Moles

Moles are usually non-cancerous (also known as benign) and will cause no symptoms. But, some moles can develop into a cancerous tumour (malignant melanoma), especially in people who are overexposed to the sun. Melanoma can sometimes also run in families.

  • Some of the most characteristic symptoms of a malignant melanoma are:
  • An itchy and painful mole
  • Change in color, especially if the mole becomes darker
  • Increase in the size of mole
  • The mole bleeds without cause

Many people believe that hair growing in a mole is a worrying sign. However, it is quite common to have hair growing out of moles and this is not a sinister feature.

In addition, many moles undergo a characteristic pattern of change. They can change color and become slightly raised or develop a warty surface. In their final stage of development, certain moles may lose some or their entire color and become more raised up and dome-shaped. These can be often seen on the face, while those on the trunk may become pedunculated (stalk-like) and resemble a skin tag. Nonetheless, many moles disappear in late adult life.

Differences between Moles and Freckles

Freckles are small light brown flat spots that appear following sun exposure usually in fair-skinned people. Unlike moles, they normally fade during winter and are darker and more numerous in summer. Freckles are usually smaller and lighter in color than moles. They can also be a sign of sun damage and a warning to fair-skinned people to protect themselves from excessive sun exposure. However, freckles have no risk of developing malignant melanoma.

Other skin growths that may be confused with moles are:

  • Seborrheic keratosis. These are raised warty lesions often brown/black in color and have a stuck-on appearance. They usually occur on the back, trunk or in the groin area and are common in older people. These skin growths have no risk of developing melanoma.
  • Dermatofibroma. These growths often appear on the legs but can also occur elsewhere on the body and are often light brown in appearance. They feel like a pea under the skin and sometimes have a dimpled surface. Dermatofibromas are harmless lesions and have no risk of developing melanoma.

Causes and Risk Factors for Moles

Moles are caused by the localised increase in the number of pigment cells, called melanocytes, in the upper layer of the skin. Some of these clusters of cells appear before birth and are seen at birth as congenital moles. Moles may also arise spontaneously, although they are more likely to occur in sun-exposed sites and in people who have a lot of exposure to the sun.

The number of acquired moles increases with age. They are relatively rare in young children but increase in later childhood and teenage years. The number of new moles appearing decreases around the age of 30. However, it is not unusual to develop new moles in a person’s 30s and 40s, but after that it becomes uncommon.

That is, excessive sun exposure is the main cause of the growth of moles later in life. Other contributing factors include skin type and color, heredity and age.

Potential Health Risks

Most moles are completely harmless and do not pose a health risk. However, a very small percentage may go on to develop a serious skin cancer called a malignant melanoma. If a person has a very large number of moles (more than 100) on their skin, this may be an indication of a tendency towards melanoma. Such people should be particularly careful of the sun and check their moles regularly, especially if there is a family history of melanoma.

Some types of moles seem to have a greater risk of developing melanoma. These include:

  • Congenital mole is a type of mole that is present at birth. These moles may increase in size and become darker or develop hair growth later. This happens especially during puberty. They are also believed to have an increased risk of developing a melanoma but in the majority of cases this does not happen. This risk is thought to be greatest in giant moles (garment congenital naevi) that are greater than 20cm in diameter (8 inches). Giant moles happen to be the most difficult to remove.
  • Atypical moles are moles that have unusual features, such as irregular border or color variation. They may look like a melanoma but are actually benign. Because of their suspicious appearance they may be excised but this is not usually necessary. But, people with lots of atypical moles may have an increased risk of developing melanoma, especially if there is a family history and, therefore, they need to check their skin carefully.

When to See a Doctor

It is important that people check their moles carefully and get someone else to check those they cannot see. If any of the following changes occur, they should have their mole examined by a doctor:

  • Asymmetry. It is necessary to check that that the shape of the mole is not changing or that one half of the mole does not become different from the other half.
  • Border. People should check for any irregularity in the border or edge of the mole.
  • Color. People should watch for any change in color of the mole, particularly if it becomes darker or speckled.
  • Diameter. It is important to check for any increase in diameter of the mole. Special attention should be paid to the moles that are bigger than the blunt end of a pencil.

Treatment for Moles

Most moles are perfectly harmless and do not require any treatment. Observation is all that is needed. Sometimes, high-quality clinical photographs will be taken to observe changes. However, if certain changes in color, size or shape of the mole occur, treatment may be necessary. The two main treatments for moles are:

  • Excision. If a mole is changing or shows any worrying signs, a patient may need to be referred to a dermatologist or a plastic surgeon for assessment. If they are worried about the mole (but not sure), a biopsy will be performed to examine a small sample of the tissue under a microscope. If they find the mole to be cancerous it will be excised (cut out). The procedure will be done while the patient is awake and the area around the mole is injected with local anesthetic to numb it. Then an ellipse of skin surrounding the mole will be cut out and the small wound stitched. This will probably result in a scar, which is longer than the original mole, but is a thin straight line.
  • Laser. This technique is used occasionally for moles that are a cosmetic problem. It is not suitable for any suspicious lesions or large moles as only the top layers of the mole are destroyed. Many doctors do not recommend this procedure as it will destroy the mole so that there will be no specimen for histological evaluation and it may mask the signs of change that occur, making it difficult for a malignant melanoma to be detected.

Which Moles Should Be Removed?

A doctor will typically recommend removing the moles for one of the following reasons:

  • The mole has changed or has features suggestive of malignancy.
  • The mole is causing problems and is frequently irritated because it catches on clothes or when brushing the hair.
  • The mole is unsightly and a patient is keen to have it removed for cosmetic reasons.

Preventing Moles and Skin Cancer

It is not possible to prevent congenital moles (those that are present at birth). But people can certainly help to prevent more developing with age by protecting themselves from the sun. In addition, by protecting themselves from the sun they can also decrease their chances of developing skin cancer. Particular care should be taken of children in the sun. Some melanomas arise from moles but many arise from previously normal skin, so it is necessary to protect all of their skin, not just the moles and make a point of checking their skin monthly.

Where to Seek Advice and Help:
American Cancer Society
Skin Cancer Foundation
National Cancer Institute