Moles are growths on the skin formed by a cluster of melanocytes. Melanocytes are pigment-producing cells in the skin. They are found in the skin, eyes, mucous membranes and brain. These are the regions on the body where moles can appear.
The moles are usually round, flat or slightly elevated, pigmented, skin-coloured or slightly pink.
The colour depends on the depth where the melanocytes are distributed, as well as on their quantity.
Why do moles appear?
There is a genetic predisposition for moles. The genetic basis is significantly influenced by sun exposure. Every time the skin peels after a sunburn, smaller or larger pigment changes appear.
If moles develop in the first three years of life, we call them congenital moles, and if they develop later they are known as acquired moles.
What types of moles exist?
There are many types of moles depending on their appearance, distribution and severity.
Blue moles can appear anywhere on the body. They are characterized by a bluish-grey colour. The cells are distributed mostly in the dermis, the deepest part of the skin, which is why they have a shiny characteristic colour.
Halo nevus are common moles surrounded by a white ring or halo. These moles are almost always benign, although in rare cases they can be a sign of malignancy, which is why it is necessary to have them checked. There is an increased amount of lymphocytes around the mole leading to regression – mole disappearance.
Spitz naevus usually appears during the first two years of life. It case it develops later, it is recommended to have it surgically removed. It is up to 1 cm in size and is characterized by rapid growth. From the pathohistological and clinical point of view, it may resemble melanoma.
Reed naevus is similar to Spitz’s, but pink in colour.
Nevus Spilus (speckled lentiginous naevus ) appears in infancy as a dark macule and later develops darker speckles and papules.
Becker’s naevus is not a real mole. It is usually first noticed around puberty, and it often presents a dark patch that becomes covered with hair over the years.
Congenital moles can be smaller, up to 1.5 cm in diameter, medium, up to 19.9 cm in size and gigantic larger than 20 cm. Congenital moles carry a slightly higher risk of turning into melanoma than the ones acquired during life. It is necessary to have them checked regularly, and every change that develops needs to be sent for pathohistological analysis.
Dysplastic moles have an atypical, irregular structure. Dermoscopes have one of the three criteria required for pathohistological verification. If a person has dysplastic naevus syndrome, i.e. a large number of irregular moles, a biopsy of the ugliest of them is performed.
How are moles checked?
In recent decades, dermoscopy has been used for mole follow-up. Dermoscopy is a special technique based on criteria that indicate the existence of a benign or malignant lesions on the skin. Every drawing on the skin is registered with a dermoscope.
A dermoscope is a device that records pigmented or unpigmented skin lesions.
Based on the dermoscopic findings, it is assessed whether it is necessary to remove the mole or any tumour from the skin.
How are moles removed?
All three skin layers are surgically removed at full depth. This is the only way to completely remove a mole, without a risk that some cells will remain.
Radiofrequency mole removal does not remove a mole at full depth, so there is a possibility that some cells will remain.
A deep shave biopsy is performed by removing the mole with a surgical knife and coagulating the skin using radio waves.
Laser mole removal with CO2 laser or Erbium laser makes a mole evaporate from the skin and prevents its pH verification.
Is it necessary to have moles removed?
Moles must be removed if malignant melanoma is suspected. Malignant melanoma is one of the rare cancers that, with timely removal, can be 100% cured.
Delaying the intervention can cause the cancer to penetrate deeper and to develop metastasis.