| LENTIGO
MALIGNA AND LENTIGO MALIGNA MELANOOM |
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 WHAT IS LENTIGO MALIGNA?
Lentigo maligna is a superficial form of skin cancer, originating from pigment cells. Pigment cells (melanocytes) are found throughout the skin; these cells give the skin its color and also protect it from sunlight. These pigment cells can suffer DNA damage, usually due to prolonged exposure to sunlight, particularly UVB radiation, and then start to grow uncontrolled. In lentigo maligna, the tumor cells are only in the superficial part of the skin, the epidermis. Sometimes, the tumor cells also penetrate into the deeper part, the dermis. This is not easy, because between the epidermis and the dermis lies a strong connective tissue layer called the basement membrane. If the tumor cells are found deeper than this basement membrane, it is called a
lentigo maligna melanoma: a
melanoma that originates from lentigo maligna. The chance of a melanoma developing in a lentigo maligna is approximately 2-3%.
WHO IS AT RISK OF DEVELOPING LENTIGO MALIGNA?
Lentigo maligna mainly occurs in older people, over 60 years old, and particularly in people who have spent a lot of time in the sun. It mainly occurs in areas that have been exposed to the sun a lot, such as the face. People with light skin have a higher risk of developing lentigo maligna or lentigo maligna melanoma. It is rare in people with darker skin, because they are better protected from sunburn. Approximately 4 out of every 100,000 people develop lentigo maligna each year.
WHAT DOES LENTIGO MALIGNA LOOK LIKE?
Usually, a brown, black, or gray spot with an
irregular shape develops on the face. Sometimes a
spot contains multiple colors, light brown and dark
brown or black. Lentigo maligna can also develop on
other parts of the body, especially in sun-exposed
areas. The spots gradually enlarge over the years
but cause few symptoms. They are not painful or
itchy.
If a melanoma develops in the spot, a thicker
area is usually visible, either protruding or
growing deeper, which can cause pain.
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IS LENTIGO MALIGNA DANGEROUS?
Lentigo maligna itself isn't dangerous, but it can
develop into melanoma, a dangerous form of skin
cancer. Melanoma can grow deeply and spread to lymph
nodes and other organs, and it can be fatal.
Therefore, it's usually recommended to remove a
lentigo maligna as a precaution, if possible. The
chance of melanoma developing in a lentigo maligna
is approximately 2-3%. For someone over 65, the
chance is approximately 2.2%; for someone who
developed a lentigo maligna at a younger age (from
45), the chance is slightly higher, at approximately
4.7%.
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melanoma
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HOW IS LENTIGO MALIGNA DIAGNOSED?
Based on the location and appearance of the spot, its shape, and color, your doctor may suspect lentigo maligna. Using a dermatoscope (a special magnifying glass with good lighting) makes this even clearer and helps distinguish lentigo maligna from other skin conditions that can strongly resemble lentigo maligna, such as a
solar lentigo, a mole
(nevus), a
melanoma (malignant melanoma), or a
seborrheic wart. A solar lentigo (lentigo
solaris, lentigo senilis) is a benign pigmented spot in older adults that does not develop into melanoma.
Solar lentigo is usually light brown in color and less irregular in shape.
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If lentigo maligna or melanoma is suspected,
it is necessary to take tissue for examination in
the pathology laboratory. If possible, the entire
lesion is removed, leaving a small margin of healthy
skin around it. The advantage of this is that the
pathologist can assess the lesion as a whole.
Sometimes a lentigo maligna is very large, and it is
then not possible to remove the entire lesion for
examination. In that case, a
skin biopsy (sample) is taken from the area that appears most
abnormal.
HOW IS LENTIGO MALIGNA TREATED?
The most effective treatment is to excise the entire lesion, leaving a small margin (5 mm) of healthy skin around it as a safety margin. The entire area is locally anesthetized with anesthetic injections around and under the lesion, after which the excision is performed. The wound is then sutured. If the wound is very large, skin from another area may need to be used to close the
defect. The excised skin is sent to the pathologist, who examines it under a microscope to ensure it has completely disappeared. If there is any residue left at the edge, this area can be removed
in a second procedure. Lentigo maligna can recur after surgery in a small percentage of patients.
The pathologist examines the entire area to ensure no lentigo maligna melanoma has developed.
Melanoma treatment is different; it is excised with
a wider margin of 1 cm, and additional examination
of nearby lymph nodes is often necessary. Additional
treatments are sometimes also required. See the
melanoma brochure for more information.
Sometimes a lentigo maligna is very large or located in difficult areas of the face, making surgical removal difficult. In that case, alternative treatments are possible, such as
radiation therapy (radiotherapy),
treatment with a cream (Aldara cream, imiquimod), or
freezing with liquid nitrogen (cryotherapy). The latter two methods are less effective than surgery or radiation therapy.
Radiation therapy (Radiotherapy)
Radiation therapy is an effective treatment if the lesion cannot be removed because it is very large or in difficult-to-operate areas, such as near the eyes or on the nose. Radiation therapy is not administered all at once, as that would cause too much damage. It is divided into several smaller doses, so you will need to visit the hospital several times.
Aldara (imiquimod) cream
Imiquimod cream stimulates the body's own immune system. These immune system cells then eliminate the malignant cells. This is effective for various superficial forms of skin cancer, including lentigo maligna. It must be applied to the affected area continuously, daily for three months. Studies show approximately 77% effectiveness with 6-7 applications per week, for a total of at least 60 applications. Redness, swelling, and peeling of the skin occur at the application site, and sometimes the skin breaks down. These inflammatory symptoms are part of the treatment, but they can sometimes make it difficult to maintain the treatment for three months.
Freezing with nitrogen (cryotherapy)
In cryotherapy, the area is thoroughly frozen twice. If necessary, the skin is first locally anesthetized. After freezing, a blister, redness, and swelling may develop, and sometimes a frostbite or ulcer. The effectiveness of freezing is less than that of other methods and depends primarily on the depth of the freezing.
It may also be decided not to treat a lentigo maligna. For example, due to advanced age, or if there are other reasons for not treating it. It's always good to discuss whether treatment is truly necessary, especially since the chance of developing a melanoma is less than 5%. Waiting and monitoring the area is also an option.
IS FOLLOW-UP NECESSARY?
Regular follow-up is officially not necessary if a lentigo maligna has been completely removed. Thin melanomas also do not require follow-up, and a lentigo maligna is much less dangerous than a thin melanoma. Keep a close eye on the area and the surrounding area and make an appointment if changes or new dark spots are visible.
WHAT IS THE PROGNOSIS?
The prognosis is good; the chance of a melanoma developing in a lentigo maligna is small, and the chance of metastasis is even smaller. However, the spot does recur frequently, often at the edge of the removed area.
WHAT CAN YOU DO?
Check your skin regularly and see a doctor if you have any concerns. Acting early makes treatment easier because the area is still small.
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