Naevi, popularly known as moles, are structures formed by differentiation from melanocytes, the cells that give the skin its colour. Moles are benign growths that can appear anywhere on the body and are usually brown, oval or round. They originate from cells called melanocytes, which produce the pigment that gives the skin its colour. The moles a person will develop are probably genetically determined in advance. Some moles are present at birth, while others appear especially in youth. However, in a genetically predisposed person new moles can form throughout life.

Signs and Symptoms
Moles can appear anywhere on the body in a wide variety of forms. They may be skin-coloured or pinkish, light brown, brown or even sometimes blue-black. They are usually oval or round in shape, raised or flat, and hairy or hairless.

Moles can change over time; their growth speeds up with puberty, pregnancy and sun exposure, and new ones may appear. Congenital moles may look similar to acquired ones, but they are usually larger and hairier than acquired moles.

When should moles be taken seriously?
Moles are benign growths that can form anywhere on the body. They should be taken seriously if they change colour or shape, grow rapidly, or are located on the genital organs or mucous membranes.

Risk of Turning Cancerous
Ordinary moles very rarely become cancerous. The most important concern about moles is that a life-threatening skin cancer called melanoma, or “malignant melanoma”, can resemble certain types of mole in particular. What really matters is the early diagnosis of melanoma, which can look like a mole. For this reason a rule has been developed to help people know which changes in their moles to take seriously. Although developed for the public, this rule is also followed by doctors.

These rules are listed as the “ABCD” rules:
A: Asymmetry – one half of the mole does not resemble the other half (in colour and/or shape)
B: Border – the borders of the mole are irregular (notched or jagged)
C: Colour – the colour of the mole is not uniform (two or more colours such as brown, black, red, grey and white together; a mottled appearance)
D: Diameter – the mole is larger than 6 mm in diameter (roughly, a mole bigger than a pencil eraser.)

The presence of any one or more of the features in the ABCD rule means the person should consult a dermatologist. A mole that bleeds or develops a sore without any injury, or changes rapidly, should be seen by a dermatologist.

There are some special moles that have most of the features of the ABCD rule from the start; these are called dysplastic or atypical moles. People with such moles should be followed up by a dermatologist because of their higher risk of developing melanoma.

The risk of developing melanoma is slightly higher in congenital moles. This risk increases further if a congenital mole is larger than 2 cm.

Growths That Look Like Moles
When people look at their own skin they see a number of spots that resemble moles. Most often these are freckles, which are seen in the areas most exposed to the sun, such as the face, back and shoulders.

Especially from middle age onwards, the growths most often confused with moles are light-to-dark brown, wart-like lesions seen most often on the trunk and face; these are seborrhoeic keratoses. Seborrhoeic keratoses are superficial skin tumours produced by the body that carry no risk of becoming malignant.

Another growth often confused with moles is the brownish spots seen mostly in middle-aged people, also known as age spots. Their medical name is solar lentigo.

Treatment
Moles usually do not affect health. Only if a mole changes rapidly in shape, colour or size, or bleeds, itches or hurts, may it pose a health problem because of the possibility of melanoma. In this case the mole may need to be removed. After a mole is removed, it must always be sent for pathological (microscopic) evaluation.

Removing a mole (partially or completely) does not cause cancer. On the contrary, it gives a chance of early diagnosis. The widely held popular belief that “if a scalpel touches it, it turns into cancer” is not true. Sometimes people may also want moles removed because they spoil their appearance. Methods such as laser, electrocautery (burning) or cryotherapy (freezing) should not be used to treat moles. Moles in the beard area can sometimes be accidentally cut while shaving. This does not create an additional risk of the mole becoming cancerous, but moles in such locations may still be removed because of the discomfort they cause.

Some people may be bothered more by the hairs on a mole than by the mole itself. There is no harm in removing these with tweezers or permanent methods.

What is malignant melanoma?

It is a type of skin cancer characterised by the structure of melanocytes becoming disrupted and multiplying uncontrollably.

What are the risk factors for malignant melanoma?

* Genetics
* Ultraviolet light
* Fair skin, light-coloured eyes, a family history of malignant melanoma
* Having had severe sunburns, having many congenital moles

What are the signs of malignant melanoma?
* Growing, changing shape, irregular edges
* Itchy, painful
* Dark brown, black
* Moles that bleed or look inflamed may be melanoma.

How is malignant melanoma diagnosed?
Early diagnosis of malignant melanoma is important and life-saving. Mole examination is carried out by a dermatologist using a dermatoscope. The diagnosis is made by pathological examination of the sample taken.

How is malignant melanoma treated?
The treatment of malignant melanoma varies depending on the stage of the cancer and other factors. At an early stage, surgery is an effective treatment. In advanced cancers, chemotherapy or radiotherapy may need to be added to surgery.