What are moles?
Moles (naevi) are light to dark coloured spots or raised areas of the skin. In a mole there is a concentration of cells that can form pigment, the so-called melanocytes. The concentration of melanocytes and the extent to which they produce pigment determine the colour of the mole.
Moles attract a lot of attention because every mole carries a (very small) chance of turning into a melanoma, an aggressive kind of skin cancer that arises from “derailed” melanocytes. Depending on the shape of the mole and the nature of the pigment cells, moles are divided into different groups.
How do moles develop?
Exactly why moles develop is not precisely known. Some moles are already present at birth — these are the so-called congenital moles. Most moles develop between the ages of about 3 and 40. A hereditary predisposition seems to play an important role, as does sunburn in childhood.
Moles and melanoma
Moles have a (very) small risk of turning into melanoma, a very aggressive form of skin cancer that can spread (metastasise) even at an early stage. When a melanoma is discovered and removed early, the chance that it has already spread is small and the survival chance is excellent. Because melanoma is located in the skin and therefore clearly visible, melanomas are fortunately often discovered in time.
Which moles have an increased risk of becoming melanoma?
Small, evenly brown-pigmented moles lying on the skin are common and have a particularly low risk of turning into melanoma. Flat moles, level with the skin, that developed at a later age have a slightly greater chance. Flat, unevenly coloured moles (also called atypical moles) run a greater risk than the previous group — though it must be stressed that even the chance of an atypical mole “turning” is still very small. Some large congenital moles have an increased risk of developing melanoma; because they form a separate category, a separate article is devoted to them.
Removing moles
Raised moles lying on the skin can often be removed well by shaving or cauterising (burning away). Flat moles and spots suspected of melanoma are always removed by complete surgical excision.
What can you look out for yourself?
Moles that change gradually or suddenly are suspect and should be checked, as are moles that newly appear and look very different from the other moles on your skin. The changes to watch for are: getting larger; changing colour wholly or partly; stinging, itching and/or pain; and bleeding.
When to see a doctor
See a doctor promptly if a mole grows, changes colour, itches, stings, hurts or bleeds, or if a new mole appears that looks different from your others — a quick assessment is very important.