Melanoma - causes, symptoms, types, stages, diagnosis and treatment

The tumor is characterized by rapid progression, metastasis to all organs and systems, and a long asymptomatic course. The combination of these factors makes melanoma one of the most dangerous malignant diseases.

The situation is aggravated by the constant increase in the incidence rate. According to statistics, in European countries, melanoma is diagnosed in 10 out of 100 thousand patients. In dark-skinned residents of the USA, the indigenous population of Algeria, Zimbabwe, Uganda, Japan, Korea and China, this figure does not exceed 1.5 cases per 100,000, while among the white population of Australia and New Zealand this figure is approximately 23-30 per 100,000. In Russia, the incidence is 4 episodes per 100 thousand.

Causes of occurrence

Despite not all the achievements of science, scientists still do not know exactly what causes melanoma. In approximately 2/3 of patients, it develops from benign skin neoplasms - nevi. These are congenital or postnatal formations called moles. Dermatologists distinguish several of their types - giant pigmented, complex pigmented, blue, nevus of Ota, border nevus. In addition, there is a high probability of degeneration in xeroderma pigmentosum and Dubreuil's melanosis.

Risk factors

As a rule, the degeneration of nevi is facilitated by the influence of one or more risk factors. The main ones include:

• ultraviolet radiation, both natural and artificial;
• history of sunburn;
• fair skin and hair, blue eyes;
• burdened heredity;
• age over 50 years;
• contact with carcinogens at work;
• exposure to ionizing radiation.

Patients who have one or more risk factors should undergo regular medical examinations - this is the only way to diagnose the disease in the early stages and begin treatment on time.

Types

Doctors use several classifications of melanomas in their work. Based on the results of the pathomorphological examination, the following variants are distinguished:

• superficially spreading melanoma - atypical cells are located in the superficial layers of the skin, spreading to the sides during growth. This variant accounts for up to 75% of all melanomas;
• nodular, or nodular melanoma - found in 15% of patients - is a formation similar to a node that quickly grows in depth;
• acrolengial melanoma - a tumor that spreads radially. Diagnosed in 10% of patients. It is localized on the soles, palms, under the nails, in places where the skin passes into the mucous membrane - lips, perineum;
• malignant lentigo - the tumor is very similar to freckles, the rarest option.

By the presence of the superficial growth phase, we, at NIARMEDIC on Botkinsky, distinguish:

• melanomas without superficial growth;
• melanomas characterized by superficial growth;
• unclassified melanomas.

Stages

Depending on the prevalence of the process, melanoma can be of the following stages:

• 0 - melanoma in situ - do not spread beyond the basement membrane;
• I - the tumor thickness is no more than 2 mm, the surface is intact or ulcerated, there are no metastases;
• II - the thickness increases to 4 mm, there are ulcers on the tumor surface, the process is limited to the primary focus;
• III - there are metastases in the regional lymph nodes, regardless of the tumor size;
• IV - diagnosed in the presence of distant multiple metastases. Most often, melanoma affects the liver, bones, and brain.

Symptoms

The diagnosis of "melanoma" can only be refuted or confirmed by a pathomorphological examination. However, there are a number of symptoms, upon the appearance of which the patient should immediately consult a doctor. The very first is the appearance of itching at the location of the nevus. Almost simultaneously, its surface becomes ulcerated and the surface bleeds. This is often associated with mechanical damage, postponing a visit to the doctor. Gradually, the mole increases in size, its edges become uneven, the color changes. In some cases, it takes the form of a node, which in its external outlines resembles a head of cauliflower.

Diagnostics

The main method for diagnosing melanoma at an early stage is dermatoscopy - examining a mole with magnifying devices. It can be carried out both with a regular magnifying glass and with a dermatoscope. In the latter case, the device makes the surface layer of the horny epithelium transparent, which significantly increases the informative value of the examination.

A preliminary diagnosis can be made based on the following dаta:

• asymmetry of the formation;
• uneven edge;
• non-uniform pigmentation;
• minimum diameter exceeds 6 mm;
• externally noticeable changes occurring with the mole.

The effectiveness of simple dermatoscopy is 60%. The use of digital technologies increases this figure to 90%.

The final diagnosis is made only based on the results of histological and cytological studies. They are carried out after radical removal of altered tissues. The depth of germination of atypical tissues and the mitotic index are of key importance. Preoperative biopsy is contraindicated, since after it melanoma progresses rapidly.

In addition, the patient is recommended to undergo a series of examinations to exclude metastases. The level of lactate dehydrogenase in the blood indicates liver damage. To detect changes in the lymph nodes and other internal organs, computed tomography, magnetic resonance imaging, and radioisotope scintigraphy are used. This approach allows for the most objective assessment of the patient's condition and the development of an appropriate treatment plan.

Treatment

At the initial stage, the main method of treating melanoma is surgery. When removing the tumor, the surgeon captures 1 to 3 cm of surrounding healthy tissue and subcutaneous tissue. This makes it possible to remove pathological cells that are invisible to the naked eye. As options, surgery under a microscope, as well as intervention using laser technologies, are possible.

In the presence of metastases, the methods of choice are chemotherapy, immunotherapy, and radioactive irradiation. Of particular interest are monoclonal antibodies and interferon-alpha. According to the results of recent studies, they can stop the growth of melanoma and increase overall survival.

Today, clinical trials of FDA-approved cytostatic agents are being conducted in foreign clinics, to which foreigners are invited. As a rule, the proposal to participate in the study is made by the attending physician, based on the available information about the patient's health.

Prevention

Unfortunately, specific preventive measures that could prevent the development of melanoma have not been developed. The main thing to pay attention to is the elimination of risk factors. First of all, you need to use sunscreens, the coefficient of which corresponds to the skin phototype. It is also necessary to exclude contact with carcinogens.

If there are unmodifiable risk factors (age, genetic predisposition, nevi), it is necessary to undergo preventive medical examinations at least once a year - this will allow changes to be detected at the earliest stages.