Melanoma of the Skin
Melanoma is a serious skin cancer that begins in pigment-producing cells called melanocytes. It can develop within an existing mole or appear as a new spot, and it can occur anywhere on the skin. If untreated, melanoma can spread to other parts of the body, so early assessment is important.
The ABCDE guide can help identify a spot that should be checked. It is a guide only: it cannot diagnose or rule out melanoma, and a melanoma may not show every feature.
A is for asymmetry: one half of the spot looks different from the other.
B is for border irregularity: the edges may be uneven, notched, blurred or poorly defined.
C is for colour variation: the spot may contain uneven shades of brown, black, blue, grey, red, pink or white.
D is for different: the spot looks unlike your other moles or freckles. Diameter can also be a clue: many melanomas are larger than 6 mm, but melanoma can be smaller.
E is for evolving: the spot is new or is changing in size, shape, colour, surface, elevation or symptoms. Itching, tenderness, crusting or bleeding may also occur.
Some melanomas are flat, small, evenly coloured, pink or red and may not resemble a typical mole. If you notice any new, changing, unusual, bleeding, painful or non-healing spot, contact your GP or dermatologist promptly. Do not wait for it to become larger or raised, or for every ABCDE sign to appear.
Different types of Melanoma
Superficial spreading Melanoma: The most common type of melanoma of the skin, accounting for 70% of all melanomas. It commonly occurs on the back or chest in men and on the legs in women. It is generally slow growing at first, tending to grow outward and spread out across the surface of the skin. This type of melanoma does not usually spread to other parts of the body until it begins to grow downward. Superficial spreading melanoma varies in colour, usually with different shades of black and brown. It is usually flat and irregular in shape.
Nodular Melanoma: The second most common type of skin melanoma and grows more quickly than other types of melanoma. It is commonly found on the chest, back, head or neck and tends to grown downward (vertical growth) rather than outward (radial growth). Nodular melanoma usually starts as a raised area that is dark blueish-black or blueish-red. However, some nodular melanomas are flesh-coloured.
Lentigo Maligna Melanoma: Commonly found in older people, it occurs in areas of high sun exposure such as the face and the neck and is slow growing. Lentigo maligna melanoma is usually tan to brown in colour and varies in colour throughout. It usually appears as a large, flat abnormal skin area.
Acral Lentiginous Melanoma: A rare type of melanoma that occurs on the palms of the hands, soles of the feet or under the nails. Like nodular melanoma, it is usually aggressive and changes rapidly from radial to vertical growth. Congenital melanocytic naevi are birthmarks or large moles that are present at birth or may develop in early childhood. There may be one or more present.
What can cause Melanoma?
Ultraviolet radiation: Exposure to ultraviolet radiation is the most important risk factor for the development of all types of skin cancer. The sun is the main source of ultraviolet radiation (UVR). Most cases of melanoma are caused by exposure to UVR from the sun.
Indoor tanning equipment: Tanning beds and sun lamps) are also a source of UVR. Having a tan means that your skin has been damaged by exposure to ultraviolet radiation.
Personal history of skin cancer: People who have already had melanoma have a higher risk of developing another primary melanoma. Having had basal cell carcinomas or squamous cell carcinomas is also linked with a higher risk of developing other skin cancers, including melanoma.
Family history of skin cancer: Your risk of developing melanoma increases if one or more of your first-degree relatives have been diagnosed with melanoma. First-degree relatives include your father, mother, brother, sister or child.
Atypical moles: An atypical mole (dysplastic naevus) is an unusual mole that looks different from an ordinary mole. Such lesions are more likely than ordinary moles to develop into melanoma. Atypical moles are most commonly found on the back, breasts, buttocks, chest and scalp and can be found on sun-exposed and non-exposed sites.
Familial Atypical Multiple Mole Melanoma (FAMMM) Syndrome: FAMMM syndrome is an inherited condition and such individuals have many moles (more than fifty), and also one or more first or second-degree relatives with melanoma. People with FAMMM have a very high risk of developing melanoma.
Weakened Immune System: People with a weakened immune system have a high risk of developing melanoma. The immune system can be weakened by certain diseases and individuals on immuno-suppressant medication following an organ transplant.
CDKN2A Gene Mutation: Around 5 – 20% of families with a high risk of melanoma have an inherited gene mutation in the CDKN2A gene. This gene is normally a suppressive gene, which means that it helps control the growth of cancer cells. Where there is a gene mutation, cancer may develop.