Melanocytic Naevi

What are melanocytic naevi (moles)?

The term melanocytic naevi is used to describe brown pigmented moles that appear anywhere on the skin surface. They are usually brown in colour and vary in skin tone form light brown to black. Occasionally, they are skin coloured or pink. Generally, they appear in childhood and the development of new lesions may continue until the age of 40 years. After this age, they tend to remain static and eventually disappear from the skin in older people. Sun exposure is known to increase the number of moles that develop in childhood and larger raised moles are often seen to be inherited in families.

Types of melanocytic naevi

Congenital Melanocytic Naevi are present at birth and can be cosmetically disfiguring if they occur on the face, hands or other sensitive sites. They do not normally require treatment although there is a small increased risk of skin cancer called malignant melanoma in larger lesions. Any change in a congenital naevus should be shown to your doctor or a dermatologist.

congenital naevus trunk congenital naevus leg congenital naevus thigh

Intradermal Melanocytic Naevi are skin-coloured or pink. They commonly appear on the face and grow slowly. They may be removed by shaving them from the skin surface using a scapel blade or a special razor blade. This normally requires an injection into the skin with a local aneasthetic. The cosmetic result is usually very acceptable although there is a small risk of a depressed scar, re-growth of the mole, loss of colour in the skin (hypopigmentation) and pigmentation of the scar base.

     
Congenital Naevus Trunk Congenital Naevus Leg  

Compound Melanocytic Naevi are raised moles that often contain dark hair and dark pigment. They are due to of an overgrowth of the main structures of the skin and are often inherited in families. They may cause cosmetically embarrassment if situated on the face. They can be shaved-off from the surface of the skin after a local anaesthetic injection. However, there is an increased risk of hair re-growth and re-pigmentation when compared to the treatment of intradermal naevi. Complete removal of the naevus can be achieved by cutting out the full thickness of the skin and stitching the edges of the wound together. This produces a scar in the skin.

     
Congenital Naevus Trunk Congenital Naevus Leg  

Halo Naevi are flat moles that become completely surrounded by a white halo of discolouration of the skin. This surrounding halo extends outwards over a number of months to years before the central pigmented area disappears. Eventually, the outer halo of skin re-pigments and the skin returns back to normal. They frequently develop in children and may be multiple. They are completely harmless and do not require any treatment. Halo naevi rarely develop in adults aged over 45 years.

 
halo naevus cheek halo naevus close-up  

Blue Naevi are raised moles that are heavily pigmented and appear blue in colour due to the melanin that is situated in the deeper layers of skin. They commonly occur in children and are more frequently seen in Asian or Oriental races. Any new blue naevi appearing in adults should be examined by  a dermatologist to exclude a skin cancer. A skin biopsy may be required to exclude a malignant melanoma. In children, they are normally harmless and do not require any treatment.

     
halo naevus cheek halo naevus close-up