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Melanomas are malignant cancers that develop on the skin in the melanocyte cells where melanin (the pigment that gives skin its colour) is produced. Other areas where this cancer can develop are the eyes and, rarely, the intestines.
Melanomas will develop when an abnormality occurs in the melanocytes on the skin. Usually this can be attributed to DNA damage in cells which then grow out of control and form malignant masses.
The reason why this DNA damage occurs is not clearly understood, but the theory is that exposure to ultraviolet (UV) rays from the sun and tanning beds results in this problem. This theory still doesn't explain why melanomas can develop in areas of the skin that don't receive UV light exposure, so there may be a genetic link associated with these lesions.
Signs and symptoms
Melanomas can develop anywhere on the skin, but they usually occur on the sun exposed areas such as the arms, legs, face and back. This skin cancer can also develop in hidden areas such as the palms of the hands, in the fingernail beds and on the soles of the feet, and this usually occurs in people with darker skins.
People mistake normal naevi (moles) as being melanomas, but there is a way one can distinguish the difference and also know when a naevus starts becoming problematic, although melanomas can also develop by themselves without starting out as a normal naevus.
The ways to identify a melanoma is to look at the following aspects, think ABCDE, and if these changes do occur then it's suggested to consult with a healthcare practitioner as soon as possible:
- Asymmetry - these skin lesions have an asymmetrical look to them, so one should try note if the two halves look different.
- Border - melanomas have irregular borders that can be scalloped or notched as well.
- Colour - these lesions usually have multiple colours in them.
- Diameter - look out for growth in a mole of more than 5 millimetres.
- Evolving - a mole that grows in size or changes colour should be assessed further. Also, other signs such as an itching or bleeding lesion should make one suspicious for a melanoma.
Making the diagnosis
People with risk factors for developing melanomas should consult with their healthcare practitioners on a regular basis in order to undergo a head-to-toe exam so that any suspicious lesions can be addressed appropriately. Any changes in skin lesions or the development of new ones in these individuals should be noted and discussed with their doctors.
The diagnosis of melanoma is made by performing certain tests:
- Punch biopsy - a blade is pressed into the lesion and a round piece of skin is removed.
- Excisional biopsy - the entire lesion or mole is removed together with a small border of normal skin.
- Incisional biopsy - the most irregular part of the lesion or mole removed.
These specimens are then sent for analysis to determine if the lesion is a melanoma or not. If the diagnosis is confirmed, then it will be reported whether the entire melanoma was removed, what stage the cancer is and whether further treatment is necessary.