Lentigo maligna

What are the aims of this leaflet?

This leaflet has been written to help you understand more about lentigo maligna. It will tell you what it is, what causes it, what can be done about it, and where you can find out more information.

What is lentigo maligna?

Lentigo maligna is one type of the earliest stage of a skin cancer called melanoma.
The word ‘melanoma’ comes from the Greek word ‘melas’, meaning black. Melanin is the dark pigment that gives the skin its natural colour and is made in the skin by pigment cells called melanocytes. After our skin is exposed to sunlight, the melanocytes make more melanin, and so the skin becomes darker.

Melanocytes may grow together in harmless groups or clusters, which are known as moles. Most people have between 10 and 50 moles and often they are darker than the surrounding skin.

Melanomas can arise in or near to a mole, but can also appear on skin that looks quite normal. They develop when the skin pigment cells (melanocytes) become cancerous and multiply in an uncontrolled way. They can then invade the skin around them and may also spread to other areas such as the lymph nodes, liver and lungs.

Lentigo maligna is a type of melanoma called ‘in situ’ melanoma. ‘In situ’ means that the cancer cells have not had the opportunity to spread anywhere else in the body. There are cancer cells in the top layer of the skin (the epidermis) but they are all contained in the area in which they began to develop. They have not started to spread or grow (‘invade’) into deeper layers of the skin. This is why some doctors call in situ cancers ‘pre-cancer’.

Lentigo maligna is a slow growing condition which can take years to develop. It appears in skin that has had a lot of sun exposure, usually the face, neck or upper arms.

Lentigo maligna can be cured with surgery. However, if the whole area is not removed completely with the appropriate surgery, some may develop into an invasive melanoma. It is therefore important to have it removed with a rim of normal skin (an adequate surgical margin). There are also preventative measures which can be taken (see below) that will further lower the risk of recurrence in the future.

What causes lentigo maligna?

The most important cause is exposure to too much ultraviolet light in sunlight. It is especially common in white-skinned people who live in or frequently visit sunny countries. The use of artificial sources of ultraviolet light, such as sunbeds, also raise the risks of melanoma. Older people are the most prone to develop lentigo maligna, especially those who have multiple harmless patches of darkened skin (solar lentigines) on their faces or the backs of their hands. These marks are sometimes called ‘age spots’ or ‘liver spots’ but are actually nothing to do with the liver; they are related to many years of sun exposure.

The risk is increased if another family member has had a melanoma. People who have already had one lentigo maligna melanoma have an increased risk of getting another one.

Lentigo maligna occurs most often in fair-skinned people who tan poorly, but is also seen in darker skin types.

Is lentigo maligna hereditary?

No, but it is more likely to develop if you have a close relative who has had melanoma. Genetic factors are less likely in lentigo maligna than in other types of melanoma, as sun exposure is by far the most important risk factor.

What are the symptoms of lentigo maligna?

Lentigo maligna appears as a long-standing brown patch, most commonly on the face, which slowly enlarges and develops darker areas. Most in situ (very early) melanomas do not cause any symptoms. If a lentigo maligna is not treated promptly, it could become hard and lumpy, bleed, ooze or crust.

What does lentigo maligna look like?

The ABCDE system (below) tells you some of the things to look out for.

A melanoma may show one or more of the following features:

  • Asymmetry – the two halves of the area differ in their shape.
  • Border – the edges of the area may be irregular or blurred, and sometimes show notches.
  • Colour – this may be uneven. Different shades of black, brown and pink may be seen.
  • Diameter – most melanomas are at least 6 mm in diameter.
  • Evolving – rapid change in a pre-existing mole.

However, this system is less useful for lentigo maligna than for other melanoma types. It is usually an enlarging brown mark on the face that is larger and/or darker than other marks, but can rarely be skin-coloured or pink.

What should I do if I am concerned about a mark on my skin?

See your family doctor promptly if you are concerned. The ABCDE changes listed above can occur in in harmless growths, and the family doctor may be able to put your mind at rest. However, if there is still any doubt, your doctor will usually refer you to a Dermatologist.

How is the diagnosis of lentigo maligna made?

A Dermatologist will examine the area carefully, usually with a magnifying device called a Dermatoscope, which is placed on the skin. This will help the Dermatologist decide whether the area needs to be looked at more closely under the microscope. This may involve removing the whole area under local anaesthetic (a procedure known as an excision) and the tissue is sent to the laboratory to be examined. If the area is too large to remove easily, a sample of it (an incisional biopsy) may be taken. If a lentigo maligna is found, the pathology report will provide information that will help to plan the next step in treatment.

Can lentigo maligna be cured?

Yes, the outlook for lentigo maligna is excellent. It is very rare for them to come back because they were ‘in situ’. Furthermore, they will not have had an opportunity to spread elsewhere in the body.

How should lentigo maligna be treated?

The main treatment for lentigo maligna is surgical. There is no other treatment of proven benefit and usually no other tests are needed.

Depending on how much tissue was removed in the first operation, some people who have had a lentigo maligna removed will need a second operation to further reduce the risk of it coming back at the original site. During this operation, some healthy skin will be removed from around the original scar to make sure that all the melanoma has been taken away, and this makes the scar larger than before. Occasionally a skin graft will be needed.
In selected cases, the area is removed using a technique called Mohs surgery. This is where the abnormal cells are taken away a layer at a time, to ensure it is fully removed, whilst trying to limit the size of the wound.
For some people, it is not possible to remove the entirety of the abnormal area because of the size, location or because the edge of the abnormal cells merge with normal skin. In these specific cases, Doctors may advise alternative treatments including application of a cream, such as imiquimod, freezing with liquid nitrogen or radiotherapy. Although these treatments are less invasive, they are not used routinely as there is a higher risk of it coming back when compared with surgery. Laser treatment also carries a high risk of recurrence.
Other factors such as age may mean it is desirable to avoid surgery and observe the area for change.

If surgery leaves any noticeable scarring, you may wish to consider advice on skin camouflage techniques.

The British Association of Dermatologists and other health organisations such as NICE (National Institute for Health and Clinical Excellence) state that people who have had a lentigo maligna surgically removed do not need any follow up visits with their specialist. This is because in situ melanomas are very unlikely to come back once the area has been removed surgically. Due of the excellent outlook of lentigo maligna, you will usually be seen once again in clinic after surgery and then discharged.

Self-care (What can I do?)

Once the lentigo melanoma has been treated, it is possible to get back to a normal lifestyle quite quickly. However, there are a few sensible precautions that can be taken to help prevent getting another one, as below:

  • Look at all areas of your skin monthly for moles that are growing, or changing in the ways listed in the ABCDE rules (see above). If you find any worrying changes, see your family doctor promptly.
  • You must also protect yourself from too much sun. This means that you need to avoid sunbathing, sunburn and tanning. You can do this by covering yourself up and using sun protection creams, especially if on holiday in a hot country (see the ‘top sun safety tips’ below for more information).
  • Do not use sunbeds or tanning lamps.
  • Share sun advice and other information with your relatives as they also may be at increased risk of getting a melanoma. In particular, protect children from the sun, as exposure during childhood seems to be particularly damaging.
  • Having had a melanoma may affect life or health insurance, particularly for the first five years after diagnosis. However, some insurance companies may be more flexible, if it is confirmed that the melanoma was a lentigo maligna, which was ‘in situ’ and not invasive, and was completely excised.

Top sun safety tips

  • Protect your skin with adequate clothing, wear a hat that protects your face, neck and ears, and a pair of UV protective sunglasses. Choose sun protective clothing (with permanently sun-protective fabric, widely available for adults and children) if you have fair skin or many moles.
  • Spend time in the shade between 11am and 3pm when it’s sunny. Step out of the sun before your skin has a chance to redden or burn. • When choosing a sunscreen look for a high protection SPF (current recommendations are SPR 50 or 50+) to protect against UVB, and the UVA circle logo and/or 4 or 5 UVA stars to protect against UVA. Apply plenty of sunscreen 15 to 30 minutes before going out in the sun, and reapply every two hours and straight after swimming and towel-drying.
  • Keep babies and young children out of direct sunlight.
  • The British Association of Dermatologists recommends that you tell your doctor about any changes to a mole or patch of skin. If your GP is concerned about your skin you are advised to see a Consultant Dermatologist – an expert in diagnosing skin cancer. Your doctor can refer you for free through the NHS.
  • Sunscreens are not an alternative to clothing and shade, rather they offer additional protection. No sunscreen will provide 100% protection.


Vitamin D advice

The evidence relating to the health effects of serum Vitamin D levels, sunlight exposure and Vitamin D intake remains inconclusive. Avoiding all sunlight exposure if you suffer from light sensitivity, or to reduce the risk of melanoma and other skin cancers, may be associated with Vitamin D deficiency.

Individuals avoiding all sun exposure should consider having their serum Vitamin D measured. If levels are reduced or deficient they may wish to consider taking supplementary vitamin D3, 10-25 micrograms per day, and increasing their intake of foods high in Vitamin D such as oily fish, eggs, meat, fortified margarines and cereals. Vitamin D3 supplements are widely available from health food shops.

Where can I find more information about lentigo maligna and melanoma in situ?

This leaflet may not have answered all of your questions, but we hope it has helped. It is completely normal not to remember what your doctor or the nursing staff tells you initially at diagnosis. For this reason, they often say the same things to you a number of times. In many departments, a skin cancer specialist nurse is available to go through the information in more detail and to act as a contact link for patients when needed.

Links to patient support groups:

Cancer Research UK
PO Box 123, Lincoln’s Inn Fields
London, WC2A 3PX
Tel: 020 7242 0200
Web: www.cancerhelp.org.uk
Other useful websites:

Jargon Buster: https://www.skinhealthinfo.org.uk/support-resources/jargon-buster/

Please note that the BAD provides web links to additional resources to help people access a range of information about their treatment or skin condition. The views expressed in these external resources may not be shared by the BAD or its members. The BAD has no control of and does not endorse the content of external links.

This leaflet aims to provide accurate information about the subject and is a consensus of the views held by representatives of the British Association of Dermatologists: individual patient circumstances may differ, which might alter both the advice and course of therapy given to you by your doctor.

This leaflet has been assessed for readability by the British Association of Dermatologists’ Patient Information Lay Review Panel


Download File