What are moles?

Moles are growths on the skin that are usually brown or black. Moles can appear anywhere on the skin, alone or in groups. Most moles appear in early childhood and during the first 20 years of a person’s life. Some moles may not appear until later in life.

It is normal to have between 10-40 moles by adulthood. As the years pass, moles usually change slowly, becoming raised and/or changing colour. Often, hairs develop on the mole. Some moles may not change at all, while others may slowly disappear over time.

What causes a mole?

Moles occur when cells in the skin grow in a cluster instead of being spread throughout the skin. These cells are called melanocytes, and they make the pigment that gives the skin its natural colour. Moles may darken after exposure to the sun, during the teen years, and during pregnancy.

Types of Moles

Congenital naevi are moles that appear at birth. Congenital naevi occur in about one in 100 people. These moles may be more likely to develop into melanoma(cancer) than are moles that appear after birth. If the mole is more than 20 centimetres in diameter, it poses a significant risk of becoming cancerous. Dysplastic naevi are moles that are larger than average (larger than a pencil eraser) and irregular in shape. They tend to have an uneven colour with dark brown centres and lighter, uneven edges. These moles tend to be hereditary (passed on from parent to child through genes). People with dysplastic naevi may have more than 100 moles and serves as a marker for developing melanoma, a serious form of skin cancer. Any change in amole should be checked by a dermatologist to detect skin cancer.

How do I know if a mole is cancer?

Most moles are not dangerous. The only moles that are of medical concern are those that look different than other existing moles or those that first appear after age 20. If you notice changes in a mole’s colour, height, size, or shape, you should have a dermatologist (skin doctor) evaluate it. You should have your moles checked if they bleed, ooze, itch, appear scaly, or becoming painful.

The following ABCDEs are important characteristics to consider when examining your moles. If a mole displays any of the signs listed below, have it checked immediately by a dermatologist. It could be cancerous.

Asymmetry: one half of the mole does not match the other half

Border: The border or edges of the mole are ragged, blurred or irregular     

Colour: The color of the mole is not the same throughout or has shades of tan, brown, black, blue, white, or red.

Diameter: The diameter of the mole is larger than the eraser of a pencil. If a mole has suddenly become greater than 6mm, it should be evaluated.

Elevation: A portion of the mole appears elevated or raised from the skin

Evolution: A sudden change in a mole should raise a concern and the mole should be evaluated.

Melanoma is form of skin cancer. The most common location for melanoma in men is the back and in women, it is the lower leg. Melanoma is the most common cancer in women ages 25-29.

What can I do if I have many moles?

One should rather be cautious than sorry. A patient with a history of multiple moles or a family history of melanoma should be evaluated by a dermatologist once every 6 months. If there are any suspicious signs, they should be evaluated earlier.

Apart from clinical examination, evaluation of the moles by means of mole mapping (computerised digital epiluminescence microscopy), is a novel technique whereby changes in moles can be detected at an earlier stage. It also establishes a baseline or control for future evaluation of moles.

How are moles treated?

If a dermatologist believes a mole needs to be evaluated further or removed entirely, he or she will either remove the entire mole or first take a small tissue sample of the mole to examine thin sections of the tissue under a microscope (a biopsy). This is a simple procedure.

If the mole is found to be cancerous, and only a small section of the tissue was taken, then depending on the depth of the lesion, the dermatologist will remove the entire mole and a rim of normal skin around it.