Lentigo Maligna is a precursor to melanoma, a form of skin cancer that can spread. It sometimes happens that malignant pigment cells develop in liver spots due to gradual degeneration of pigment cells or melanocytes. This is called lentigo maligna. Lentigo maligna is an early stage of melanoma. The term ‘lentigo’ refers to the brown spot that is visible and ‘maligna’ means ‘malignant’. Malignant, because lentigo maligna is the last stage before melanoma. Damage to the skin due to excessive exposure to sunlight is the main cause.
- Lentigo maligna melanoma: key points
- What is lentigo maligna melanoma?
- Synonyms
- Cause of a lentigo maligna
- Symptoms of lentigo maligna
- Brown to black colored spot
- Lentigo maligna melanoma
- Who gets it?
- Examination and diagnosis
- Treatment of lentigo maligna melanoma
- Surgical removal
- Non-surgical removal
- Treatment with the cream imiquimod
- Prognosis
Lentigo maligna melanoma: key points
- Lentigo Maligna is a precursor to melanoma.
- Lentigo Maligna is often caused by excessive exposure to sunlight.
Fig. 1: Melanoma / Source: National Cancer Institute, Wikimedia Commons (Public domain)
- A slowly growing, brown to black, irregular spot is visible on the skin.
- A suspicious spot will almost always be surgically removed.
What is lentigo maligna melanoma?
Lentigo maligna is also called melanosis praecancerosa or morbus Dubreuilh and is a slowly growing skin disorder. It is an early stage of melanoma (see figure 1, a form of skin cancer that starts from pigment cells or melanocytes), which mainly occurs in areas that are frequently exposed to the sun, especially on the face. The abnormality usually arises from lentigo benigna (liver spots or age spots, see image 2). ‘Lentigo’ refers to the brown spot that occurs and ‘maligna’ means ‘malignant’.
Synonyms
Other names of lentigo maligna are:
- melanosis praecancerosa
- morbus Dubreuilh
- Dubreuilh’s disease
Fig. 2: Age spots / Source: Alain Gérard, Wikimedia Commons (CC BY-SA-4.0)
Cause of a lentigo maligna
The abnormality is a pigment change that usually arises from lentigo benigna, in which malignant pigment cells develop as a result of chronic exposure to sunlight. People with an outdoor profession and a white skin color are most at risk.
Symptoms of lentigo maligna
Brown to black colored spot
Clinically they are light brown to dark brown or black, irregular but sharply defined macula (= color change in the level of the skin). The size of the spot varies, but is often larger than 1 cm in diameter. The abnormality normally does not cause any complaints, but sometimes there is some itching.
Lentigo maligna melanoma
Lentigo maligna is premalignant and when tumor cells become invasive, the lesion is called lentigo maligna melanoma (LMM). The literature shows that approximately 5% of lentigo maligna spots develop into an LMM at some point. At this stage it can also spread and threaten life.
Who gets it?
Most patients are over 60 years old.
Examination and diagnosis
The diagnosis can usually be made based on the clinical symptoms. If in doubt, the area is examined with a dermatoscope (a hand-held microscope for the skin) or a biopsy is taken, in which a piece of tissue (the biopsy) is removed and sent for further examination to the pathologist or microbiologist who will further assess the piece of tissue.
Treatment of lentigo maligna melanoma
Surgical removal
In most cases, the lentigo maligna is surgically removed. The surgeon excises the area with a wide margin (of at least five millimeters) around the lesion to ensure that no abnormal tissue remains.
Non-surgical removal
If the site is too large for therapeutic excision (the surgical cutting of the site), radiotherapy (radiation), cryotherapy (a treatment using freezing), laser treatment and topical treatment with imiquimod (a cream) can be considered.
Imiquimod is prescribed by the doctor and must be collected from the pharmacy / Source: Istock.com/Wavebreakmedia
Treatment with the cream imiquimod
Imiquimod is a cream that inhibits cell growth and improves the skin’s defenses. This medication is not only prescribed for lentigo maligna melanoma, but also for condylomata acuminata (special type of genital warts) and actinic keratoses, also called ‘sun damage’ of the skin. The main side effects of this medicine are itching and pain on or around the affected area and light spotting of the treated area. Sometimes itching and pain may occur on or around the wart, rarely with swelling, flaking or excoriation. Five years after use, light spots may appear on the skin where the cream has been applied. Rarely, stinging, burning, redness and other irritation occur when you apply the product. This usually disappears after a few minutes. Sores, scabs and blisters on the area where you applied the product also rarely occur, as does discoloration of the skin in and around the treated area. This discoloration can be irreversible. Headache, nausea, fatigue and muscle pain also sometimes occur. Consult your doctor if you experience any of these or other side effects. The dosage may need to be adjusted.
Prognosis
Lentigo maligna is a slowly growing skin tumor, which can develop into a melanoma, which is known as lentigo maligna melanoma (LMM). How long that will take is unknown in 2023. In about 25 to 50% of cases there is a risk of malignant degeneration. Once the diagnosis has been made, it is important to have the abnormality removed as soon as possible.
read more
- Skin disorders AZ: symptoms, cause and treatment
- Lentigo, liver spots, age spots: face, arm, hand
- Age spots on face: removal and treatment
- Age warts: removal and treatment on face
- Actnic keratoses: symptoms, cause and treatment