Malignant melanoma is one of the most dangerous types of skin cancer. It is one of the most common cancers among 20- to 35-year-olds. Melanoma can occur at any age, but it is extremely rare in childhood.

The causes of malignant melanoma are not fully understood. Sun exposure during childhood and adolescence is thought to be an important contributor to melanoma risk and seems more important than exposure later in life. The worst damage is thought to occur following occasional exposure to short periods of intense sunlight causing sunburn, such as at weekends or on holiday. The higher incidence of malignant melanoma in indoor workers compared to outdoor workers supports this notion.

People with a history of melanoma in another family member and people with numerous moles are at a higher risk of melanoma.

All forms of skin cancer have been on the increase in most fair-skinned populations, the highest rate of increase worldwide is noted for malignant melanoma.  The rise could have occurred because having a tan became more desirable over the years, and people started to sun-bathe more.  It could also have been due to people exposing more of their body to the sun, as shorts/short skirts/sleeveless tops have become more popular.  Another possible reason is the ozone depletion in the stratosphere that is allowing more UVB penetration from the sun.

Malignant melanoma may arise as a new mole or as changes in colour, shape, size or sensation of an old spot, freckle or mole. Melanomas tend to have an irregular outline and an irregular colouring. Itching is a common symptom but is also found in normal moles.

It is important to note that whether a mole is flat or raised, whether it has gradually become fleshier over a long period, or whether it has hairs protruding is not an indicator of melanoma.

If recognized and treated early, the chances of survival are good. If untreated, the tumour can develop rapidly, and cancer cells can spread to other parts of the body causing death.