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The melanoma (ex nævocarcinome) is a shrewd tumor developed from the melanocytes.
The melanocytes are in skin, the mucous membranes, the eyes, and the central nervous system.
The frequency of the melanoma increases in the world. .. Reasons and factors of risk
The reasons are unknown, but factors of risk have been individualized.
The illness touches the light-skinned topics a lot more.
The importance of the phototype is demonstrated by the character exceptional of the shrewd melanoma at people with black skin. Inversely, at people of Caucasian type, the inability to tan and the tendency to the sunburns, the blue eyes, blond or redhead hair, the clear complexion, the presence of éphélides (freckles) are factors of risk knew.
The risk of melanoma decreases when the degree of pigmentation increases.
The exhibition is in the sun a factor of risk, especially as it was intense and had place in the first 15 years of life.
The solar explosions are followed of peaks of frequency of the melanomas.
A hereditary factor exists.
In some cases, these hereditary factors are major: domestic shrewd melanomas and BK-Mole syndrome.
The domestic shrewd melanomas are defined by two melanomas or more in only one family. They represent 1 to 6% of all melanomas.
The BK-Mole syndrome (B and K are the initials of the patronymics of the first two patients at the time of the individualization of the syndrome; Mole means nævus in English) is the association at several members of a same family of shrewd melanomas and nævus dysplasiques.
The nævi dysplasiques is particular nævi by their clinical and histological aspect. This syndrome is hereditary, dominant autosomique, to strong pénétrance. He/it represents 95% of the cases of domestic melanomas.
The topics having some nævi dysplasiques in the setting of the BK Mole syndrome have a big risk to develop a shrewd melanoma. The antecedents of domestic shrewd melanoma outside of the BK Mole syndrome represents a factor of risk.
Most shrewd melanomas are of spontaneous apparition; there are only 20 of them to 40% that take birth from a pigmentary nævus.
The degeneration of a nævus is therefore rare. It is necessary to question a degeneration if the nævus:
* Changed color, became polychrome with extension of the pigmentation on the healthy skin; * enlarged, rose, is himself souvert of squames or a crust; * ulcerates or bleed; * Scrapes.
The number and the size of the nævi (diameter superior to 2 cm) constitute a scorer of risk importing but these nævi is not the precursors obligatory of the melanoma.
The mélanose of Dubreuilh (shrewd lentigo or LMM: lentigo malignant melanoma)
It is the least serious shape that touches the aged topic.
This melanoma appears on the face or another cutaneous zone exposed in the sun. It is a big stain without functional sign, of 2 to 6 cm, hover, brunette or of hauled coloration, with points of pigmentation more dark, brunette or black irregularly disposed to his/her/its surface.
A pigmented cupboard, often to the level of the face, spreads progressively. The malignancy is merely local. After about ten years, a nodule invasif can constitute itself.
The complete exérèse is an efficient treatment..
The melanoma to superficial extension (extensive superficial shrewd melanoma or SSM = Superficial Spreading Melanoma)
He/it appears to all age after the puberty, often between 30 and 50 years.
Him seat in general on the back at the man, on the leg at the woman.
To the departure, it is a small brunette or black pigmented stain of 5 to 10 mm of diameter, asymmetric, irregular. The bluish, gray or pink beaches and the pigmented zones achieving the characteristic aspect of a polychrome lesion to irregular contours in card of geography appear beyond 10 mm.
This dark brown stain is often confounded in the beginning with a benign pigmentary nævus but some signs should worry:
* Transformation or recent extension noticed by the patient; * Modification of size, of color, of aspect, of consistence, of shape; * Irregularity of the sides; * Polychromy of the lesion
Less the melanoma penetrates in the dermis, less it is thick, better is the prognosis; it is the notion of initial local malignancy.
The tumorous thickness determines the indication of Breslow:
it is the most important prognostic indicator. It is an objective and reproducible method that consists in measuring vertically to the ocular micrometer the thickness since the granular of the epidermis until the deepest tumorous cell.
The nodular melanoma
It is a more serious shape.
It is characterized by a more vertical progression of the tumor that is thus more aggressive than the other types of melanomas. The prognosis is more unfavorable because the thickness of the lesion is of straightaway elevated.
He occurs to all age (20-60 years) on a nævus preexisting or on a healthy skin. He/it forms a black nodule of fast growth, becoming quickly budding and hémorragique. The motive usual of concern is a fast extension of protuberant, dark papules or a plate. The coloration varies the gray formed to the black. .. Exams and complementary analyses
The exérèse of all lesion suspected to be a melanoma imposes itself for the histological exam.
In case of confirmation, a balance of extension is undertaken:
* Research of ganglia; * X-ray of the lungs; * cerebral Scanner; * hepatic Scintigraphie.
The metastases make themselves by blood and lymphatic way.
.. Differential diagnosis
Numerous lesions colored by the pigment mélanique or the blood pigment can be taken for shrewd melanomas.
But the recent growth, the bleeding, the ulceration, or the apparition of a darker hue are indications to the exérèse or to the biopsy of the pigmented lesions.
The precocious diagnosis is possible if the biopsies are made on lesions presenting:
* Of the multi-colored colors (brown or black with red, white or blue reflections); * Of the visible or palpable irregular reliefs; * Of the irregular limits with indentations and notches.
The prevention rests on the promotion of the precocious tracking, particularly justified and efficient concerning melanoma.
..Melanomas: Treatment
The surgical exérèse of the initial lesions imposes itself.
The only means to treat efficiently and to get an optimal prognosis is to track down précocément the tumor by the inspection and to practice a biopsy in order to appreciate histologiquement his/her/its thickness.
..Melanomas: Prevention and tracking
The factor of most known risk of shrewd melanoma is the exhibition to the rays ultra-violet, notably intense and repeated during short periods. The role of the exhibition in the childhood has been underlined lately. The prevention consists in avoiding the solar exhibitions at the hottest hours of the day, to protect skin by covering clothes and/or creams antisolaires total screen. This advice especially addresses to the light-skinned topics tanning little or not, especially if they are carriers of multiple nævi or syndrome of the nævus dysplasique.
The precocious tracking of the shrewd melanoma permits to treat some tumors to a stage where they are curable.
The clinical and photographic surveillance of the topics to risk is counseled.
The prevention of the melanoma imposes the limitation of the pollutions susceptible to reduce the atmospheric sun protection, the information of the populations on the risks of the solar radiance, a very included individual sun protection adapted to every phototype, and finally the tracking of the individuals to high risk of melanoma.
* A brunette or black stain on the skin that alters (in size, in shape, in color, in contour) in some weeks or months, outside of the childhood, impose a fast consultation;
* No one is placed better than oneself or his near to supervise his skin; * to Remove a suspected mole is a simple gesture, without danger,; to remove it too late can sign the stop of death; * If the family's member presented a melanoma or if the topic is carrier of a big number of flat, larger moles than a diameter of pencil, it is predisposed to develop a melanoma; * More the number of moles is raised, more the complexion and hair are clear, more the risk to develop a melanoma is big. This risk is especially clean than the exhibition was in the sun important.
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