Moles, also known as melanocytic nevus (plural: nevi) are small lesions in the skin. They are a collection of melanocytes. Melanocytes are melanin-producing cells. Melanin is a pigment which gives our skin its color. Moles are usually brownish, but some may be much darker, while others are skin-colored. They can be rough, flat, raised, and have hair coming out of them. They are generally round or oval, and have a smooth edge.
Moles can change in appearance and numbers. Sometimes they eventually fade away or drop off. Some moles respond to changes in hormone levels, as may occur during pregnancy, adolescence and older age. During our teen years they usually grow in number, get darker during pregnancy and gradually fade away when we are older.
The majority of moles appear during the first 20 to 30 years of a person's life, however, some may be present when the baby is born. Congenital Melanocytic nevi are present at birth, any moles appearing after birth are melanocytic nevi. Dark skinned people generally have fewer moles than those with fair skin.
Most moles are inherited. People brought up in sunny places tend to have more moles than others with the same type of skin who were raised in areas with comparatively little sun exposure.
Sun spots, which may be caused by severe sunburn, are not moles.
If you have moles, you should check them regularly for changes in texture and/or appearance.
Types of Moles
An example of what was considered a normal mole. In this case the edges were deemed to be even, not ragged and not notched. Part of the ABCDs for detection of melanoma. Source: National Cancer Institute
- Junctional melanocytic nevi - usually round, flat and brown.
- Dermal melanocytic nevi - usually raised, sometimes has hair, skin colored or light brown.
- Halo nevi - the skin around it has lost its color, so it has a white ring around it, hence the name. When the mole eventually fades away, the skin regains its color.
- Dysplastic nevi - also known as atypical nevi or Clark nevi - can be flat or bumpy, is large, the edges may be irregular and do not change over time. It is an unusual looking mole.
Older people tend to have seborrheic keratoses. These are not moles; they may look like them, but they are blemishes. They look like raised warts. They can be gray, brown, yellowish or black. They are more commonly found on the tummy and chest.
Freckles are not moles.
Symptoms of moles
A symptom is something the patient feels and reports, such as pain, while a sign is something other people can also identify, such as a rash.
In general, moles are brown; however, they can come in a variety of sizes, shapes and colors:
- Shape - they can be oval and round
- Color - they are usually medium-to dark brown, reddish brown, or flesh colored
- Size - moles can vary enormously in size. They can cover an entire arm, or be as small as a pinhead. Typically, they are less than 6 mm (1/4 inch) long.
The average human has from 10 to 14 moles. They can develop on the scalp, under the nails, armpits, virtually anywhere on the body. The total number of moles a person can have usually varies during their lifetime.
A mole's surface can be raised, wrinkled, flat or smooth. They may start out with one color and be flat, and then become slightly raised, and the color may lighten. Some may develop a small stalk, and gradually wear off. Often, moles will disappear completely.
Most moles appear during early life, up to the age of about 20 years, however, they can continue appearing until middle age.
Moles that emerge after the age of 20 should be shown to a doctor. You should also see your doctor if a mole itches, has a burning sensation, is painful, bleeds or oozes, is crusty or scaly, or suddenly changes in color, elevation, size or shape.
While people with more than 50 moles may be at higher risk of developing melanoma, people who have fewer moles may be at greater risk of developing more aggressive melanoma.
The number of moles on one's right arm could be used to predict the risk of melanoma - the deadliest form of skin cancer - according to a new study by researchers from King's College London in the UK.
Possible complications of moles
Some moles can become cancerous. Especially:
- Congenital nevi - these are large moles that people are born with. They raise the individual's risk of developing malignant melanoma, an aggressive and potentially fatal type of skin cancer.
- Moles that appear in families - atypical (dysplastic) nevi are larger than normal and are usually hereditary. Individuals with dysplastic nevi have a higher risk of developing malignant melanoma than other individuals.
- Many moles - people with numerous moles run a greater risk of developing malignant melanoma.
Diagnosing cancerous moles
People, especially those with numerous moles, should check them regularly for changes in size, color or shape. In the majority of cases, mole changes are nothing to worry about, they are usually due to benign increases in pigment cells in the skin. Benign means non-cancerous.
If you visit your doctor about a mole you are concerned about, they will ask you to describe when you detected the changes, and your family history of moles and any complications.
NICE (National Institute for Health and Clinical Excellence), UK, has a seven-point checklist GPs (general practitioners, primary care physicians) use when assessing a mole:
- Does the mole cause pain, itching or a change in sensation?
- Does the mole have an irregular color?
- Does the mole have an irregular shape?
- Has the mole changed in size?
- Is the mole 0.28 inches (7 mm) across or more?
- Is the mole oozing?
- Is the mole red and swollen (inflamed)?
If the changes to the mole are mild, the doctor may take a clinical photograph of it and measure its dimensions. The patient will be asked to come back after a few weeks to see whether any of the dimensions have changed.
If the GP suspects there are signs of malignancy, the patient will be referred to a specialist, usually a dermatologist.
The dermatologist will either cut the mole out (excision biopsy) or say that the mole is not cancerous. Ideally, the entire mole is surgically removed in one go. If it is in a difficult location, this might not be possible.
The removed mole will be sent to a lab and viewed under a microscope for signs of cell changes.
If lab results come back with a suspected melanoma, further tests may be ordered to determine whether the cancer has spread.
Treatments for moles
The majority of moles are harmless and require no treatment. They may be surgically removed if:
- The mole is a suspected melanoma
- It is bothersome, e.g. the patient finds shaving difficult, or it gets snagged in clothing.
A mole may be removed in several ways:
- Shave excision - the area around the mole is numbed, a small blade is used to cut around and under the mole. A technique commonly used for smaller moles. No sutures (stitches) are needed.
- Excisional surgery (excision biopsy) - the mole plus a surrounding margin of healthy skin is cut out using a scalpel or a punch device. Sutures are required.
If the melanoma is detected in the very early stages, when the mole is thin and has not grown downwards from the surface of the skin and spread to other parts of the body, it is removed using a simple surgical technique.
If it is detected in later stages, it will be removed, plus some healthy skin around it - called a safety margin. If the cancer has entered the bloodstream or lymphatic system and formed tumors in other parts of the body, the patient will require further treatment.
Protecting yourself from skin cancer
If a mole is going to form, it will form, there is nothing you can do to prevent that. However, you can reduce the chances of developing malignant melanoma.
Regularly check your moles for any changes.
Limit the amount of time your skin is exposed to sunlight.