Melanoma, medically referred to as malignant melanoma, is a type of cancer that arises from the skin’s pigment-forming cells, known as melanocytes. These cells are responsible for the production of melanin, the pigment that gives the skin, hair and eyes their color. This type of cancer is particularly worrying because it has a tendency to spread (metastasize).

Symptoms of melanoma

Here are some common symptoms of melanoma, also known as malignant melanoma:

Changes in existing moles:

  • Enlargement or change in shape.
  • Change in color, such as a darker hue or uneven color distribution.
  • Bleeding or fluid discharge from the birthmark.
  • Uneven, jagged or blurred edges.

New skin changes:

  • A new birthmark that grows quickly.
  • A mole with a diameter of more than 6mm.
  • A mole that itches, hurts or feels uncomfortable.

Other signs:

  • Redness or swelling around the mole.
  • Swollen or thickened skin around the mole.
  • Changes in the skin near the mole, such as crusting, peeling, or pigment changes.

If you experience one or more of these symptoms, it’s important to seek medical attention for an accurate diagnosis. Early diagnosis and treatment of melanoma is crucial for a good outcome. These symptoms may not necessarily be signs of cancer, but you should still take them seriously. They can be signs that you are developing cancer.

“ABCDE” rule

The “ABCDE” rule is a smart mnemonic when checking moles for warning signs. If you have one or more moles that meet one or more of the ABCDE criteria, you should be aware.

  • Asymmetry: The birthmark is asymmetrical.
  • Border: Irregular or blurred edges.
  • Color: Multiple colors in the same mole or change in color.
  • Diameter: Over 6 mm in diameter.
  • Evolving: Changes in size, shape or color over time.

Common skin cancer is not melanoma

It is important to distinguish melanoma (malignant melanoma) from regular skin cancer. Read more about skin cancer.

What does melanoma look like?

We’ve collected images with examples of what melanoma can look like.

Understanding the underlying causes and risk factors for melanoma is an important step in the prevention and early detection of the disease. Although the exact cause of melanoma is not fully understood, there are a number of known factors that can increase the risk.

Sun and UV exposure

The most well-known risk factor for melanoma is excessive exposure to ultraviolet (UV) radiation from the sun or tanning lamps. UV rays can cause damage to skin cells, which can lead to abnormal cell development and possibly cancer.

Skin type and age

People with fair skin, blue eyes, and red or blonde hair have a higher risk of developing melanoma. The risk also increases with age, although melanoma can affect people of any age.

Genetics and familial risk

If there is a family history of skin cancer or melanoma, the risk of developing the disease may be higher. Certain genetic syndromes, such as familial malignant melanoma, can also increase the risk.

Previous skin problems

A history of sunburn, especially during childhood or adolescence, can increase the risk of melanoma later in life.

It is important to note that the presence of one or more risk factors does not necessarily mean that a person will develop melanoma. But it does increase the importance of regular skin checks and preventative measures.

The diagnosis of melanoma often starts with a simple observation: you or your doctor notices a change in a mole or a new growth on the skin. However, the full diagnostic process involves a number of steps that can vary depending on the individual patient’s symptoms and medical history.

Skin examination

The first step in diagnosis is typically a thorough skin examination. The doctor will examine all areas of the skin, including areas you may not have noticed yourself, to identify suspicious growths.


In some cases, your doctor may use a dermatoscope, a specially designed microscope, to take a closer look at the mole. This provides a more detailed assessment and can help determine if further testing is necessary.

Microscopic examination

If a mole or skin lesion looks suspicious, the next step is often to remove the mole. The removed element is then sent to a laboratory for microscopic examination.

Additional tests

If the biopsy shows that cancer is present, further tests may be required to determine the stage of the disease. This can include blood tests, X-rays, and various types of imaging scans such as CT, MRI or PET scans.

The treatment and monitoring of melanoma is only carried out at public hospitals in Denmark. So, if you are diagnosed with melanoma, the subsequent treatment will take place in public hospitals.