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Healthy skin cells divide in an orderly way to replace dead cells and grow new skin. Abnormal skin cells are unable to grow and divide normally; these are cells which have the disease "skin cancer". These abnormal cells can grow out of control and form tumours, if the abnormal cells originate on the skin they are often called "skin tumours".

If a skin tumour does not invade surrounding organs or tissues and is limited to a few skin layers it is considered benign.

If the skin tumour spreads to surrounding organs or tissues it is called cancerous or malignant.

Symptoms of skin cancer

Skin cancer can normally appear as an abormal accumulation of cells, it can take the form of a changing mole, a growth or a sore/pimple that does not heal. The growth may itch, bleed, crust or scab, or change size, shape or colour.

Most common symptoms

  • a new growth or mole on the skin
  • a change in an existing skin growth or mole
  • a sore or pimple that does not heal

Not all of the changes on the skin are key symptoms of skin cancer. Many people have moles and other skin growths which are benign:

  • Birth marks or congenital nevi - these are moles present at birth
  • Skin tags - soft flaps of small skin that are caused by repeated friction. They often occur in the armpits, on the neck and groin area.
  • Acquired moles - these develop between adolescence and teenage years. Through the teenage years they may grow in size, shape and darken in colour.
  • Liver spots, or "solar lentigines", are flat tan-to-brown spots that occur mainly on the face, neck, hands, and forearms. They have nothing to do with the liver. Rather, they develop as a result of aging and sun exposure.
  • Seborrheic keratoses - these are tan/brown, raised wart like growths which occur on the skin as people age. 

Clink on the video link below for reminders on how to check your skin: