Many people do not know about the nature of moles and due to the fact that these formations do not bother them during their life, they do not even remember their existence. What is a nevus from a medical point of view? This is an accumulation of pigment cells on the surface or in the skin layer, which is a congenital or acquired phenomenon. Such spots can be of different sizes - from 0.5 to 10 cm in diameter. The location on the torso, the size of these formations are initially embedded in human DNA and are already in the newborn, but are not visible until a certain age.
Skin nevi are acquired or congenital formations of a benign nature and consisting of an accumulation of melanocytes. That is, this includes birthmarks or moles that are present in any person and are a malformation of dermal cells. Ordinary nevus is a very common phenomenon that does not require any therapy and does not pose a threat to human health. However, they come in different types, some of them tend to degenerate into malignant formations.
In addition, skin nevi do not always represent a congenital pathology, often they arise throughout life. As a rule, until a person comes of age, their size and quantity can increase, and then decrease slightly. This fact is due to the simultaneous growth of nevi along with the body. After the maturation period, the increase in moles also stops.
In accordance with the international classification of diseases (ICD), skin nevi are code D22.
Causes of occurrence
The causes of birthmarks are violations of the process of migration of melanoblasts, which are the precursors of melanocytes. As a result of such a violation, an area of their significant concentration is formed, where the skin nevus subsequently arises. Specialists divide them into congenital and acquired, but some experts are of the opinion that such a classification is conditional. This opinion is connected with the fact that moles that occur in adults are not newly formed areas of concentration of melanoblasts, but are congenital, but they appeared only after a while.
The main reasons contributing to the formation of moles during the period of intrauterine development include:
- Hereditary factor.
- The pathologies that accompany pregnancy (toxicosis, the threat of miscarriage).
- Exposure to radiation and ionizing radiation.
- Exposure to allergic and toxic agents.
- Acute forms of infectious pathologies of the genitourinary system in pregnant women.
Provocative factors
The following factors can provoke the development of acquired moles:
- UV exposure to the skin.
- Pregnancy, during which hormonal bursts are noted.
- Skin diseases of an infectious nature.
- Skin diseases of allergic origin.
- Mechanical trauma to the skin.
- The use of contraceptives.
- Hormonal bursts during puberty.
Below we consider the main types of moles.
Varieties, classification
Acquired and congenital skin nevi may have a similar structure. This reason makes it appropriate to classify according to their histological structure. This allows you to take into account the main features of each mole and with a high probability to predict their subsequent development. Specialists distinguish about 50 varieties of nevus, but most often about 10 of them are found. First of all, all moles are usually classified into two varieties:
- Melanoma hazardous (melanomorphic).
- Melanoma-hazardous.
Formations of the second type almost never degenerate into malignant. Therefore, the recommendation for their removal is mainly cosmetic in nature.
Melaniform nevus of the skin is characterized by a high probability of degeneration into a malignant tumor. Such formations are almost always recommended to be removed.
Among the melanoma-hazardous, the following are distinguished:
- Intradermal pigmented.
- Halonevuses.
- Fibroepithelial.
- Papillomatous.
- Mongolian spots.
Mongolian spot
It is a pigmented nevus of the skin of the congenital type, most often found in newborns belonging to the Mongoloid race. This variety is inherently a genetic variant of the violation of the process of pigmentation of the dermis. In most people, the Mongolian spot disappear by the age of five. They are localized, as a rule, on the sacrum and buttocks. Sometimes a Mongolian spot persists for life, and does not disappear. But even in such cases, it does not degenerate into a malignant formation and does not require therapy.
Papillomatous appearance
Papillomatous nevus of the skin has an unsightly appearance, which often scares its carriers. That is why people often consult with oncologists, suspecting the worst development of the situation. Papillomatous intradermal nevi of the skin is characterized by a strong elevation, difference in color and shape from the rest of the dermis. The surface is dobelous, brown. Such a nevus does not cause subjective sensations, except for psychological discomfort, if the place of its position is hands, neck, face. The favorite place for localization is the scalp, limb, and trunk. Throughout life, papillomatous nevi change their characteristics. They can become a different color, increase in size, but it is extremely rare to degenerate into malignant formations.
Fibroepithelial nevi
The most common type of mole is fibroepithelial. It can be both congenital and acquired. Often, such nevi appear against the background of hormonal changes in the body. However, medicine has information about the occurrence of moles of this type in the elderly. Most often, the fibroepithelial nevus has a rounded shape, pink color, elastic consistency. For some time, the mole grows, then this process slows down, and its progress stops. Cases of degeneration of fibroepithelial nevus are extremely rare.
Nevus Setton
Sometimes it is called halonevus. It is exclusively acquired, develops in people with malfunctions of the hormonal system, autoimmune pathologies, and decreased immunity. The development of halonevus triggers a reaction in which the body struggles with its own cells. It is characterized by an oval shape, it rises slightly above the skin. The name of the nevus is consonant with its form. The central part of the mole is more intensely pigmented than the edges. This color visually resembles a halo - an optical phenomenon that forms around the moon or the sun. The central (main) part of the nevus is located inside the pale zone. Removing such formations is not recommended, as they may indicate the presence in the body of other, serious pathologies. Halonevuses almost never degenerate into a cancerous tumor.
Other varieties
Intradermal pigmented skin nevuses most often develop during puberty. At the initial stages of their development, they are located inside the cover, on its surface does not protrude. Typically, nevi of this type are small in size, but over time they can change - change their own shape, color. They are not inclined to progression in old age, which cannot be said about moles of other types. Only in rare cases do they degenerate into malignant formations.
Many are interested in the fact that this is a melanocytic nevus of the skin. The following varieties are commonly referred to this group:
- Blue.
- Giant pigmented.
- Nevus Ota.
- Dysplastic.
- Border pigmented.
The border pigment mole is most often a congenital neoplasm, but in some cases it can manifest itself in the first years of a child’s life. As a rule, nevi of this type grow in proportion to the growth of the body. If a person grows intensely, the size of education also increases greatly. Such nevi rise slightly above the skin and are characterized by a high accumulation of melanin, which is responsible for the dark color of the mole, which can be dark purple, dark brown, even black. There is no clear localization place for this type of mole; it can occur on any part of the body. A characteristic feature is that only borderline pigmented nevus can occur on the feet and palms. Malignancy may indicate its dense consistency.
Dysplastic nevi
Dysplastic nevi of the skin are both congenital and acquired. Moles of this type in many patients arise during puberty, are family in nature (often found in several family members). They are usually located in the axillary, inguinal folds, on the hips, legs, and in the upper back. Skin nevi appear, as a rule, as a group, however there are cases of a single occurrence. The color of such spots can be different - from light brown to black. Quite often, a peculiar pigmentation is observed on the periphery and in the center of the spot. Accurate diagnosis requires a biopsy to detect a typical accumulation of cells. In about 90% of cases, dysplastic nevi degenerate into malignant formations - melanomas. In this regard, the appearance of such a mole requires radical removal and appropriate therapy.
Nevus Ota
Ovus nevus is characterized by a large accumulation of melanin. As a rule, such elements are single in nature, however, there are also multiple formations that are prone to fusion. It is a neurodermal nevus. In this case, the formation of moles occurs under the influence of neurological factors. It is considered a nevus of the skin of the face - usually located on the edge of the orbit or on the cheekbones. It appears in the form of a blue-black spot located in the cornea or on the white of the eye. A characteristic feature of the Ovus nevus is that it is able to change the mucous membranes of the eye, in particular if it has a large size.
Such an education is a congenital phenomenon and genetic etiology. Most often found in the Mongols and Japanese, less often in other Asians and Chinese. Ota is not often transformed into a malignant nevus, but this likelihood remains. A significant role in degeneration is played by ultraviolet.
Giant nevus
Giant pigmented nevuses are congenital formations and, unlike other congenital birthmarks, are noticeable from the birth of a child. Progress as the body grows and reaches significant size. Often, such a formation is not just localized on a large area of the dermis, but occupies the entire anatomical region, for example, the trunk, neck, half of the face. Medicine has registered cases when the sizes of giant pigmented nevuses reached 40 cm. In a similar situation, we can talk about a significant cosmetic defect, since the mole strongly protrudes above the surface of the dermis and is regarded as a massive tumor that worsens the appearance of a person. The color of the spot in most cases varies from gray to brown. Its structure can be diverse, for example, small warts, grooves, cracks can be located on its surface, increased hairiness can be observed. It is these characteristics that make it possible to distinguish giant pigmented nevi from other types.
Therapy of such formations is carried out in order to remove a cosmetic defect. Only in rare cases is it malignant. Often this happens after it is removed. However, doctors claim that a nevus of such a large size is often injured, and this, in turn, contributes to its degeneration. They remove it by surgical excision of the tumor and subsequent skin transplantation.
Blue nevus
It is a benign formation, although it indicates a precancerous condition. Their name is determined by color. However, moles can be not only blue, but also black, dark purple, gray, dark blue, blue. Blue nevi consist of a significant accumulation of melanocytes actively producing melatonin. As a rule, they are single, but rashes of a multiple nature are also found. Such moles appear slightly above the skin, and palpation of the formation makes it possible to detect the intradermal node of a dense structure. Such a nevus does not have a clear localization; it can occur in any areas. Its boundaries are clear, the diameter does not exceed a centimeter, hair growth is not observed on it. The degeneration of the blue nevus occurs, as a rule, as a result of constant trauma or after incomplete removal. It is worth noting that the transformation itself is very rare.
Mole Diagnosis
The main objective of the process for diagnosing skin nevi (according to ICD code D22) is to differentiate the formation of malignant melanoma and other diseases of the dermis. In this regard, the oncologist dermatologist will first of all exclude the malignant form of the pathology, and then determine the variety and the appropriate therapy.
For this purpose, the following diagnostic methods are used:
- Sonography.
- Histological examination.
- Biopsy.
- Thermometry.
- Diagnostics of phosphorus isotopes.
- Dermatoscopy
Dermatoscopy is performed using a special apparatus that magnifies the image tens of times and allows you to detect the slightest changes on the surface of the nevus. Currently, this technique is most effective in the early diagnosis of melanoma. However, dermatoscopy does not allow with full confidence to refute or confirm the diagnosis, but can only tell the doctor the next diagnostic tactics. The diagnostic method is absolutely painless, as it is non-contact and does not involve any effect on the patient’s skin.
Diagnosis with a phosphorus isotope involves the accumulation of radioactive phosphorus by a malignant formation. With melanoma, this substance accumulates in the nevi, which indicates enhanced cell division in its structure and allows us to talk about the presence of cancer.
Thermometry involves a local measurement of the temperature of the dermis. The procedure is carried out using a special apparatus. During the study, the temperature on the surface of a healthy dermis is compared with the temperature on the surface of the skin nevus (according to ICD 10 code - D22). If the formation is benign, then the difference in indicators will be about one degree, and if malignant - about 2-2.5 degrees.
The most reliable diagnostic method is a biopsy, which involves taking a biopsy and its subsequent microscopic examination. A biopsy can be puncture and excision. The last variety of the procedure is also therapeutic, when the birthmark is removed and its subsequent histological examination. This technique allows you to most accurately establish the diagnosis, but it is used only in the case of superficial nevi.
Therapy
Therapy of skin nevi (ICD code - D22) involves their surgical removal. They can do this for aesthetic or medical reasons. Aesthetic removal is necessary if the mole is a pronounced cosmetic defect.
To date, there are several methods for removing nevi:
- Surgical excision.
- Electrocoagulation
- Cryodestruction.
- Laser surgery
The most common way is the latter. The tissue of formation is evaporated by a carbon dioxide laser, as a result of which the cells in its structure die. The technique is painless, the patient only feels heat and a slight burning sensation. There are no scars or scars after laser removal. An important role is played by the location of the mole and its size. If it is on the surface, incomplete evaporation may occur, leading to relapse.
With cryodestruction, a mole is removed by exposing it to liquid nitrogen. This technique is used if the location of the formation is superficial and the size is small.
With electrocoagulation, tissue evaporation also occurs, but only with the help of electric current. The method can be used to remove only small moles.
Surgical excision occurs using a traditional scalpel. During the operation, not only the nevus is removed, but also adjacent tissues. Then, stitches are placed at the excision site. A similar operation is performed using local anesthesia.
We examined what it is - skin nevus.