Skin cancer and moles

The appearance of a new mole, or changes in an existing mole can be a sign of a type of skin cancer called malignant melanoma. So what exactly is it, why does malignant melanoma develop and what can be done about it?

What is malignant melanoma?

Malignant melanoma is an aggressive type of skin cancer that, if left untreated, can spread to the lymph nodes and then to other organs of the body, such as the liver and the lungs.

Some facts about malignant melanoma


Melanoma with Asymmetry of shape (A), irregular Border (B), multiple Colours (C), and enlarging Diameter (D).

  • Malignant melanoma is quite a rare form of cancer, with only around 13,000 cases each year in the UK. This compares to over 40,000 cases of bowel and lung cancer and over 50,000 cases of breast cancer per year.
  • Melanoma is the most deadly form of skin cancer, with over 2,000 deaths per year in the UK, accounting for the majority of skin cancer deaths.
  • Many people assume that skin cancer comes with age, after many years of sun exposure, but malignant melanoma tends to develop in young people.
  • Malignant melanoma is the most prevalent cancer amongst 15-34 year olds. It is related to known risk factors such as having a very fair skin, bad sunburn in early life and some genetic factors.

Malignant melanoma can, however, be easily and completely cured, as long as the cancer is identified early enough. With this in mind, the importance of self checking and regular appointments with a dermatologist if you are at particular risk, cannot be overstated.

What causes malignant melanoma?

Malignant melanoma arises because of a fault in melanocytes that makes them develop in an abnormal way. You are more likely to develop melanoma if you have:

  • Pale skin that burns rather than tans even on short sun exposure.
  • Ginger or light blonde hair and blue eyes.
  • Many existing moles and freckles.
  • High UV exposure e.g. from sun seeking or from working outdoors.
  • A family history of malignant melanoma.
  • A medical condition that reduces your immune system, or you are taking drugs that suppress it (if you have had an organ transplant, for example).

How is malignant melanoma diagnosed?

Suspected melanomas are identified by observing differences in your existing moles, or by looking for new moles that suddenly appear.

Dr Bowling will use dermoscopy to view all your moles in detail, to look for the earliest possible detectable changes of melanoma. For any mole looking suspicious for melanoma  the diagnosis is finally made by taking a biopsy, in which some or more typically all of the mole is removed and examined under a microscope to see if it contains cancer cells.

It is important to remember that malignant melanoma is a rare condition, and some moles that are biopsied will come not be cancerous. However it is always best to have these moles checked to be sure.


If it is caught early, the standard treatment for malignant melanoma is the surgical removal of the cancerous cells as well as a safety margin of normal skin. If all the cells are successfully removed, there is little chance that the cancer will return. If melanoma is detected at a later stage further treatment may be necessary including more surgery, immunotherapy or chemotherapy, depending on your individual case.”

Find out more about treatment for malignant melanoma.