Melanoma — the malignant tumor resulting from atipichesky regeneration and reproduction of pigmentary cages (melanotsit). Most often affects skin, but can meet also on mucous. It is characterized by bystry distribution of tumor cells on all organism. The melanoma is diagnosed according to a research of dab print made from its surface. Histologic confirmation of the diagnosis is made after removal of education. Treatment is carried out depending on a stage of a melanoma and can consist in surgical excision of education, removal of lymph nodes, an immunotherapy, radiation therapy and chemotherapy.
The melanoma is one of types of cancer of skin. 1-1,5% of all malignant new growths fall to the share of a melanoma. According to WHO data every year in the world about 48 000 people perish from a melanoma and incidence growth is noted. Most often the melanoma is diagnosed for the patients living in the southern countries in a condition of the increased natural insolation. People are subject to a disease generally 30 years are more senior, but separate cases of a melanoma occur also at children. Worldwide incidence of a melanoma of skin varies from 5 to 30 people on 100 000 population.
Causes of a melanoma
The risk of development of a melanoma is increased at persons with I and II phototypes of skin. Development of a disease in people with swarty skin and persons of negroid race is most improbable. The probability of developing of a melanoma is increased available in the anamnesis (even in the early childhood) by solar burns, excess ultra-violet radiation, both natural, and received in a sunbed. Hereditary predisposition — developing of a disease at the persons having melanoma cases in the family anamnesis is traced. Scientists assume that it is connected with genetically transferred violation in work of the supressor suppressing tumoral growth.
About 70% of cases of development of a melanoma result from malignant regeneration of a pigmentary nevus which treat: huge pigmentary nevus, blue nevus, Ott's nevus, difficult pigmentary nevus, boundary nevus. With high probability be transformed to a melanoma also pigmentary xeroderma and Dyubreyl's melanoza can. Its traumatizing and the increased insolation, hereditary and endocrine factors belong to the factors starting process of a malignization of a nevus or pigmentary education.
Classification of a melanoma
The modern dermatology classifies melanomas by phases of development and clinical types. Allocate two phases in development of a melanoma: horizontal and vertical. At the beginning of the development the melanoma grows only in the horizontal direction, without going beyond an epitelialny layer. Then there come the vertical phase and tumoral process begins to extend in below the located skin layers, passes in a term and hypodermic fatty cellulose. In a vertical phase growth of a melanoma considerably accelerates and there is its metastasis.
Depending on clinical manifestations there are 3 types of melanomas of skin: superficial extending, nodal and a lentigo-melanoma. Along with it in 1997 the international classification of melanomas by the TNM system was accepted.
- T - primary tumor classified depending on thickness of germination, existence or lack of ulcerations. Precisely is defined only after the carried-out treatment.
- N — a condition of regionarny lymph nodes.
- There is no Nx — reliable data for the correct assessment.
- N0 — signs of damage of lymph nodes are absent.
- N1 — metastasises in lymph nodes up to 3 cm in size.
- N2a — metastasises more than 3 cm.
- N2b — existence of the metastasises in skin or hypodermic fatty cellulose located at distance more than 2 cm from the main tumor (transit metastasises).
- N2c — existence of metastasises in lymph nodes more than 3 cm in size in combination with transit metastasises.
- M — the remote metastasises (which are going beyond a regionarny zone)
- — there are no data for definition of existence of the remote metastasises.
- M0 — the remote metastasises are not defined.
- M1a — the remote metastasises in lymph nodes, skin or hypodermic fatty cellulose.
- M1b — existence of metastasises in internals.
The melanoma is characterized by a big variety of a clinical picture. Both concerning an arrangement and the sizes of a tumor, and concerning its consistence and coloring. The melanoma can be roundish, polygonal, triangular or have any other form. Color of a tumor happens black, gray, brown, bluish, pink-violet and gray. And coloring can be uniform on all area of a melanoma, and can include a combination of several flowers. Also the depigmented melanomas meet.
The melanoma can have the sizes from couple of millimeters to 3 cm. Its consistence usually dense, but maybe elastic. The surface of a tumor happens not changed, izjyazvlenny, becoming wet, bleeding when traumatizing or covered with crusts. Lack of the skin drawing on a melanoma surface is characteristic. In a vertical phase of the growth the melanoma begins to tower over the surface of skin, accepting at the same time griboobrazny, nodal, hilly or spherical shape. Skin metastasises of a melanoma are shown in the form of pigmentary inclusions, small knots or hyperaemia located on tumor perimeter.
The superficial extending form of a melanoma meets in 60% of cases. At the beginning of the growth such melanoma has an appearance of a small pigmentary spot with a diameter up to 5 mm. The spot is painted in brown or black color and lies in one plane with the surface of skin. The horizontal phase of the superficial extending melanoma can stretch for the period up to 7 years. Upon transition to a vertical phase of development there is a sharp growth of a tumor and its eminence over skin level.
The nodal form of a melanoma in structure of a disease makes about 20%. The form of knot, a polyp or a mushroom is characteristic of it. Color of a tumor more often happens blue-red or black. Because the nodal melanoma originally towers over skin level, earlier was considered that it has no horizontal phase of development. However now it is proved that it not so.
Lentigo-melanoma arises at malignant transformation of a melanoz of Dyubreyl. 20% of all melanomas fall to its share. Has rather long period of horizontal growth (10-20 years). In a vertical phase of development the center of defeat becomes deckle-edged irregular shape and uneven coloring.
On lymphatic vessels the melanoma spreads in lymph nodes and skin. Skin metastasises on a clinical picture divide on nodal, satellite, rozhepodobny and tromboflebitopodobny. Nodal metastasises of a melanoma are characterized by multiple small knots of various sizes, settling down hypodermically on different removal from primary tumor. Satellite metastasises settle down around primary melanoma in the form of the pigmentary spots having the same coloring as well as primary center. The Rozhepodobny form of metastasis has an appearance of reddening and hypostasis of skin around the melanoma center. At a tromboflebitopodobny form the redness of skin and expansion of superficially located veins on the site of skin around a melanoma is observed, the dispersing radially painful consolidations come to light.
Distribution of tumor cells of a melanoma on blood vessels leads to emergence of the remote metastasises in internals: lungs, liver, bones, brain, adrenal glands, kidneys.
Diagnosis of a melanoma
The variety of a clinical picture and lack of bright symptoms at the beginning of a disease complicates timely diagnosis of a melanoma. It is possible to suspect transformation of a nevus in a melanoma at change of its color, emergence of unevenness in coloring, smoothing of its borders, increase in the sizes, disappearance of the skin drawing on a nevus surface. Emergence of reddening around a nevus, its erozirovany surfaces, emergence of cracks, bleeding or unpleasant feelings in the field of a nevus are also a reason for urgent consultation of a dermatoonkolog.
At survey of education estimate its edges, density, a smeshchayemost of rather surrounding fabrics. Carry out Dermoscopy of education and the skin surrounding it. For identification of metastasises of a melanoma examine also other sites of an integument, and also regionarny lymph nodes. Carrying out a radio isotope research is possible. The patient accepts radio medicine on an empty stomach. Then by means of radiometry estimate accumulation of isotope in the field of education and on the healthy site of skin.
In diagnosis of a melanoma the biopsy of skin education as it can cause growth of a tumor and its metastasis categorically is not applied. The main method of diagnostics is detection of atypical melanotsit when carrying out a cytologic research of dab print taken from the surface of education. However the final diagnosis of a melanoma can be made only after a histologic research of a remote tumor.
Treatment of a melanoma
The choice of a method of treatment of a melanoma depends on a phase of its development, prevalence of process and existence of metastasis. If treatment is begun in a phase of horizontal growth of a melanoma, then its surgical excision within healthy fabrics suffices. At detection of deep germination of a tumor surgical treatment is combined with immunochemotherapy alpha interferon for prevention of a recurrence. Melanoma metastasis in regionarny lymph nodes is the indication to their removal.
Detection of several melanomas demands removal all of them and additional carrying out chemotherapy, radiation of affected areas of skin or a combination of these methods with an immunotherapy. To patients with the remote metastasises of a melanoma palliative treatment is carried out: excision of the large centers of a tumor bringing to the patient the expressed discomfort. Carrying out operations on removal of metastasises from internals is in certain cases possible. Also the chemotherapy is carried out beam.
Forecast and prevention of a melanoma
Unfortunately, even at the modern level of development of medicine every third case of a melanoma comes to an end with a bystry lethal outcome. About a half of patients does not manage to prolong life longer than 5 years.
Prevention of a melanoma consists in avoiding of influence of provocative factors and an onkonastorozhennost concerning the existing pigmentary nevus. To people with light skin, especially to owners of I and II phototypes, it is necessary to avoid excessive insolation and solar burns. Restriction of influence of ultraviolet rays for those sites of skin where a pigmentary nevus is located is important. At emergence of sharp changes in the size, color or a consistence of a nevus it is necessary to consult at the dermatologist or the oncologist. Timely diagnostics and surgical excision of melanomoopasny formations of skin and often injured nevus prevents their transformation in a melanoma.