Dubreu’s precancerous melanosis or malignant lentigo is a disease that is characterized by the appearance of a neoplasm on the skin in the form of a pigment spot, a mole (nevus) or a dense nodule. Dubreu’s melanosis is an accumulation of pigment cells that are localized both in the dermis and in the epidermis. Usually the boundaries of the formation are even, clear, the surface can be smooth or papillomatous, light brown or black.
This pathology causes some controversy among specialists. Some tend to consider Dubrey’s melanosis a nevus, while others attribute it to senile dermatoses. However, all experts agree that this pathology has a high malanomo-dangerous threshold and needs serious treatment.
According to the international classification of skin neoplasms, Dubrey’s melanosis, like Bowen’s disease, is considered cancer in situ (cancer in situ), that is, obligate, preinvasive cancer. This form is a very early stage of a malignant disease, which involves the accumulation of atypical cells in the tumor, but without sprouting into the underlying tissue or internal organs.
Reasons for development
The disease develops most often in older people with fair skin. It is noteworthy that this pathology practically does not affect representatives of the Negroid race. Dubrey’s melanosis occurs with equal frequency in both men and women. However, the disease is still less common in men than in women. In men, the disease develops at the age of 50-60 years, in women at the oldest age.
Unfortunately, the exact causes that contribute to the development of Dubrey’s melanosis have not yet been identified. But indirect causes are known that can provoke the development of this disease. Its development is determined by both endogenous factors:
- increased susceptibility to ultraviolet (I, II, III skin phenotype according to Fitzpatrick);
- age after 50 years;
- the presence of keratosis;
- the presence of elastosis;
- skin atrophy.
- excessive ultraviolet radiation;
- drying of the skin as a result of its dehydration;
- excessive abuse of tan, obtained both in the natural environment and in the solarium;
- damage and injury to the skin.
Symptoms and stages of development
Dubrey’s melanosis is a pigment spot or node that has an uneven color, a varied shape, but clear boundaries. Its shades can vary from light brown to black. The favorite localization of melanosis is open areas of the skin, especially the face. Also, melanosis can be localized on the skin of the eyelids and even on the conjunctiva of the eyes.
Melanosis develops for a long time, sometimes it takes years and even decades. But, despite such a comforting sign, the vertical growth of melanosis presents some concerns, since in this case it inevitably degenerates into melanoma.
You should immediately visit a doctor if you notice the following signs indicating the transformation of melanosis into a malignant disease:
- intensive tumor growth;
- the appearance of jagged or wavy borders;
- the appearance of areas of skin atrophy;
- the appearance of papules and nodes on the affected area (which were not there before);
- change in the shape, size and structure of the spot.
Most often, pathology develops in the form of single elements, mainly in the elderly. When the spot is malignant, it usually occurs several years after the first manifestation of the disease, it increases, darker areas appear and lobular papillomas form.
There are several stages in the development of this disease:
- The first stage, which is called ephelid (freckle), is manifested by an increase in the number of cells – melanocytes.
- The second stage – lentigo implies changes in the structure of melanocytes, in other words, atypical changes accumulate in melanocytes.
- The third stage – dysplasia is manifested by the growth of atypical melanocytes into the dermis.
The disease is easily diagnosed by clinical manifestations. But in case of suspicion of melanoma, a whole range of laboratory tests is carried out:
- biopsy and morphological examination;
- testing for tumor markers.
With the help of a special apparatus that magnifies the surface image of the tumor several times, it is possible to examine the slightest change in its shape, structure and size. When conducting a biopsy and morphological examination, acanthosis and an increased concentration of melanocytes are observed.
Radioactive phosphorus scintigraphy can accurately determine the development of melanoma. Tumor markers are substances that detect in the patient’s blood or urine specific proteins produced by cancer cells.
It is necessary to carry out a differential diagnosis with the following pathologies:
- seborrheic keratosis;
- verrucous nevus
- senile keratosis.
Due to the high risk of tumor malignancy, individuals with Dubreuil’s melanosis should be followed up by a dermato-oncologist for years. In case of suspicion of malignancy of melanosis, surgical treatment is performed, which consists in excising the tumor with the removal of nearby tissue.
In the case of an inoperable form of skin cancer, radiation therapy is used. Namely, close-focus X-ray therapy.
Forecast and prevention
The earlier the diagnosis is made, the better the prognosis. Be sure to carry out the treatment of Dubrey’s melanosis, since without treatment, 75% of cases of melanosis turn into a malignant form of melanoma (letigo-melanoma). In very rare cases, spontaneous spontaneous healing occurs. That is, melanosis goes away on its own.
Prevention for this disease does not exist, since the causes of its occurrence are not entirely clear. Mandatory is the fact of protecting the skin from ultraviolet radiation and direct sunlight on moles, age spots and other skin formations.