What is skin cancer?

Skin cancer is the uncontrolled growth of abnormal cells in the skin.

Types of skin cancer

There are three main types of skin cancer:

BCC and SCC are sometimes called non-melanoma skin cancers. There are other rare skin cancers, such Merkel cell carcinoma, Kaposi sarcoma or T cell lymphoma of the skin, but these cancers are treated very differently from BCCs and SCCs. Call Cancer Council for more details.

Basal cell carcinoma (BCC)

BCC makes up about 70% of non-melanoma skin cancers.

  • It commonly develops on the head, neck and upper body.
  • It may appear as a pearly lump or a scaly, dry area that is pale or bright pink in colour and shiny.
  • BCC may bleed and become inflamed, and dead tissue may slough off (ulcerate). Some BCCs heal then break down again.

Often BCCs have no symptoms. They tend to grow slowly and don’t usually spread to other parts of the body. The earlier a BCC is found, the easier it will be to treat.

However, if a BCC is left untreated or grows larger than 5 cm, it may grow deeper into the skin and damage nearby tissue. This may make treatment more difficult and increase the chance of the BCC returning.

It is possible to have more than one BCC at the same time; having one increases your risk of getting another.

Squamous cell carcinoma (SCC)

SCC accounts for about 30% of non-melanoma skin cancers.

  • SCC usually appears on parts of the body most often exposed to the sun, such as the head, neck, hands, forearms or lower legs.
  • It often appears as a thickened, red, scaly spot or as a rapidly growing lump.
  • SCC may look like a sore that hasn’t healed.
  • It may be tender to touch, and is sometimes mistaken for a skin sore (boil).

SCCs tend to grow quickly over several weeks or months. It is possible for SCCs to spread to other parts of the body if left untreated.

Bowen’s disease (also called squamous cell carcinoma in situ) looks like a red, scaly patch. It is an early form of skin cancer found in the outer layer of the skin (epidermis). If not treated, it can sometimes develop into a SCC.


Australia has the highest rates of melanoma in the world, with over 12,500 cases diagnosed in Australia in 2012. Melanoma is considered the most serious type of skin cancer.

  • It can often appear as an existing spot that changes size, shape or colour over several weeks or months, or which continues to grow.
  • Melanoma often has an irregular edge or surface, and it may be more than one colour such as brown, black, blue, red, white or light grey. Rarely, melanomas are just one colour, such as black or red.

Left untreated, a melanoma may spread deeper into the skin where cancer cells can escape and be carried in lymph or blood vessels to other parts of the body. The earlier melanoma is diagnosed, the better the chance of cure.

For a free booklet about how melanoma is diagnosed and treated, call Cancer Council 13 11 20.

Non cancerous skin spots

Not all spots that appear on your skin are cancerous. However, freckles, moles or sunspots are warning signs that your skin has had too much sun exposure and you may be at a greater risk of developing skin cancer.


A mole (naevus) is a normal growth on the skin. Moles (naevi) develop when the pigment-producing cells of the skin (melanocytes) grow in groups.

Moles are very common. Some people have many moles on their body – this can run in families. Overexposure to the sun, especially in childhood, can also lead to more moles growing on the skin.

Dysplastic naevi

Moles that have an irregular shape and an uneven colour are called dysplastic naevi. People with many dysplastic naevi are at greater risk of developing melanoma. If you have these moles, ask your doctor how to check your skin regularly for any changes and find new skin spots. If you notice any changes, see your doctor immediately.

Sunspots (solar keratoses)

Red, scaly spots on the skin that feel rough are called sunspots (solar keratoses). They usually occur in people aged over 40 on areas of skin frequently exposed to the sun, such as the head, neck, hands, forearms and legs. Rarely, solar keratoses may develop into SCC.

Skin spots comparison

This information was last reviewed in March 2014
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