Pigmented nevus
The content of the article:
- What are nevi
- Kinds
- Causes
-
Characteristics of various types of pigmented nevi
- Borderline
- Intradermal
- Complicated
- Spindle cell
- Balloon cell nevus
- Setton's nevus, or halonevus
- Blue, or light blue
- Mongolian spot
- Nevus Ota
- Nevus Ito
- Melanocytic mixed
- Dysplastic
- Signs of malignant transformation
- Video
A pigmented nevus (birthmark) is a benign neoplasm of the skin that occurs due to a violation of the normal structure of melanocytes - pigment cells containing melanin. They originate from the nerve fold and, during embryogenesis, move to the basal (growth) layer of the skin of various parts of the human body. When the normal maturation or migration of these cells is disturbed, a congenital form of a nevus occurs. Such deformed melanocytes (nevocytes) do not have processes, are characterized by a weak metabolism and are capable of excessive pigmentation of the skin.
Moles, or pigmented nevi, occur in 90% of people
The melaniform nevus was assigned an ICD code 10 - D 22.
What are nevi
- It can occur anywhere on the body and in any age group. It is more often found on the skin from birth, and increases in proportion to the growth of the child (in case of excessively intensive growth, an immediate consultation with an oncologist is required).
- One of the most common skin lesions (80-90% of the population). More common in women. In representatives of dark races, pigmented nevi are less common than in whites.
- Does not bring discomfort to a person and does not have symptoms even in case of rebirth (10-20%). For this reason, self-observation and periodic (once a year) examination by an oncologist are recommended.
- In older people, pigmented nevi are more common due to age-related features of the skin.
- Moles are extremely sensitive to external influences (direct sunlight, for example). They tend to become malignant, especially in permanently injured areas. The only treatment is surgical removal of the mass.
Kinds
Classification of melanocytic nevi according to J. Bhawan (1979) depending on the origin:
| View | Subspecies |
| Epidermal | Intraepidermal, borderline, complex. This group also includes special forms: spindle-cell or epithelioid, nevus from balloon-forming cells, halonevus |
| Dermal | Mongolian spot, Oto nevus, Ito nevus and blue |
| Mixed dermal and epidermal | Combined |
| Precursors of melanoma | Congenital, dysplastic |
Masses of epidermal origin are usually acquired and occur during adolescence.
Size classification:
- small (0.5–1.5 cm) - only observation is shown;
- medium (1.5–10 cm), planned surgical removal of the neoplasm is optimal;
- large (over 10 cm), planned palliative therapy is indicated (surgical treatment is not always indicated due to the large area);
- giant - cover one or more anatomical regions; only palliative therapy and observation are indicated (surgical treatment is not used).
Causes
There are the following reasons for the occurrence of these neoplasms:
- Congenital features. Violation of cell migration and their redistribution between the dermis and epidermis. In children, pigmented nevi are mostly due to just such a mechanism.
- Genetic predisposition. It is associated with impaired cell proliferation of the epidermis and dermis due to hereditary defects in the structure of cells.
- The impact of environmental factors. First of all, these include the action of direct sunlight. In this case, the restructuring of the cellular structure of the nevus and the degeneration of the neoplasm into malignant forms like melanoma can occur. The second most important is the unfavorable background radiation.
- Traumatic injuries. Combing the neoplasm, traumatizing it with clothing and shoes, as well as damage due to mechanical friction of skin areas against each other.
- Incorrect treatment. In the case of an incorrect approach to treatment, a relapse of the disease may occur. This also includes attempts to self-medicate (acid moxibustion, for example).
- Ethnicity. The factor is associated with the peculiarity of the redistribution of melanocytes in different races. In particular, people with pale skin and light hair have the worst prognosis (high risk of rebirth).
- Disruption of the endocrine system (for example, changes in hormonal levels during pregnancy). It indirectly affects the formation of pigmented nevi or their degeneration, since there is a restructuring of all metabolic and metabolic processes in the body (including in the skin).
- Eating disorders. This factor is related to the development of almost any formation in the human body.
There is no single reason for the appearance of a particular variant of a pigmented nevus; often its occurrence is associated with the adjacent action of a number of factors.
Characteristics of various types of pigmented nevi
Borderline
Formed in utero (often does not appear immediately, but 1-2 months after birth). There is no favorite localization, it occurs on any part of the skin. The risk of becoming malignant is high. The prognosis is good with proper treatment.
Appearance (pictured):
- a flat focus of a round or oval shape;
- color from dark brown to black, heterogeneous color (pigmentation intensifies along the edges in the form of concentric rings);
- size from a few millimeters to 4-5 cm;
- the surface is even, the boundaries are clear;
- hair can grow on the surface of the formation;
- single or multiple;
- sometimes there is a slight infiltration around the formation.
Intradermal
It usually occurs between 10 and 30 years of age. Favorite localization - face, neck, torso. The forecast is favorable. The risk of malignancy is low.
Intradermal nevus has clear boundaries and dark color
Appearance:
- papule or node up to 1 cm in diameter (protrudes above the skin surface);
- spherical or hemispherical shape;
- the color is dark brown or black.
Complicated
It occurs in people of different ages. Favorite localization - face, scalp and torso. The prognosis is favorable, the risk of malignancy is average.
Appearance:
- up to 1 cm in diameter;
- covered with hair;
- located at skin level;
- has a light brown tint.
Spindle cell
It is also called Spitz's nevus. It predominates in children, practically does not occur at an older age. Favorite location - face, legs. The prognosis is favorable (inclined to involution), the risk of rebirth is low.
Appearance:
- more often single;
- round or oval;
- the surface is smooth (less often it can be warty);
- color from pink to dark brown;
- diameter on average 1-2 cm;
- affects the deep layers, therefore, it can bleed when injured.
Balloon cell nevus
It is more common in young people. There is no favorite localization. The outlook is conditionally favorable due to rapid growth, the risk of malignancy and average.
Externally:
- has the appearance of a spot, does not protrude above the skin;
- color from yellow to dark brown;
- has clear boundaries (yellow rim around the formation).
Setton's nevus, or halonevus
Combination of intradermal nevus with vitiligo. It can be either congenital or occur during the first years of life. It is characteristic for individuals with autoimmune diseases. There is no favorite localization. The prognosis is conditionally favorable due to the combination of a pigmented nevus and an autoimmune disease. The risk of malignancy is low.
Setton's nevus - a combination of the actual nevus with vitiligo
Appearance:
- single nodule or multiple nodules above the surface of the skin;
- diameter up to 0.5 cm;
- along the periphery there is a depigmentation zone, the width of which is 2-3 times greater than the nodule itself.
Blue, or light blue
It occurs in middle-aged people, although a violation of the normal structure of cells occurs in utero. Puberty becomes a stimulating factor for development. Common in women. Favorite localization: lumbosacral region, buttocks, rear of the hands and feet. The forecast is favorable. The risk of malignancy is low.
Externally:
- the color is dark blue, gray or brown;
- sharply delimited from the surrounding tissues;
- round or spherical;
- protrudes above the skin;
- has a smooth surface without hair;
- diameter up to 0.5 cm.
Mongolian spot
It occurs in childhood mainly in representatives of the Mongoloid race, in other races it occurs in less than 1%. Favorite places of localization: lumbosacral region, back, buttocks. The prognosis is favorable, the spot spontaneously regresses by the age of 7-13. The risk of malignancy is low.
Appearance:
- a single formation, sharply delimited from the surrounding tissues;
- oval shape;
- grayish-bluish color;
- diameter 5-10 cm.
Nevus Ota
It occurs more often at an early age or in utero, in rare cases it appears in older people. More often women are ill.
It is formed at the site of innervation of the I and II branches of the trigeminal nerve, usually unilateral. Combines damage to the eyes (pigment spot on the sclera, iris), mucous membranes (oral cavity and upper respiratory tract) with spots on the skin of the face.
Ota's nevus is more common in women
The prognosis is conditionally favorable, since it regresses in extremely rare cases, but does not significantly affect the work of all affected organs, including the eyes. The risk of malignancy is low.
Externally:
- diameter over 10 cm;
- black and bluish color;
- there are no clear boundaries;
- multiple, tend to merge (facial skin becomes as if dirty).
Nevus Ito
Located in the supraclavicular region, the lateral surfaces of the neck in the deltoid region. The forecast is conditionally favorable. The risk of malignant transformation is low.
External manifestations like Ota's nevus.
Melanocytic mixed
For example, a combination of border and blue or other combinations. They have congenital and acquired forms, affect almost any age. There is no favorite localization.
Appearance:
- elements are variable (papules, nodes);
- color from dark brown to black;
- hair can grow on the surface;
- diameter from 1.5 to 20 cm.
A special type among these formations is a giant congenital nevus. Localization - the lower back, scalp, thighs. It can be combined with malformations of a number of organs and systems (for example, with hydrocephalus). The prognosis is unfavorable, the risk of malignancy is high.
It looks like this:
- more than 20 cm;
- uneven bumpy surface;
- may be covered with hair (giant pigmented hair) or deep cracks (giant pigmented papillomatous and verrucous);
- uniform color from dirty gray to black.
Dysplastic
It can arise as a family form of the disease, heredity is clearly traced. Favorite localization - the skin of the back, lower limbs, buttocks, chest. The prognosis is poor, it is a precancer. The risk of malignancy is extremely high.
- multiple, irregular shapes;
- diameter over 5mm;
- fuzzy boundaries;
- uneven pigmentation (dark brown areas alternate with pink).
Signs of malignant transformation
Signs of the transition of a typical pigmented nevus to melanoma are as follows:
- change or heterogeneity of color;
- rapid growth;
- screenings (the appearance of small dots around the central focus);
- blurry or broken boundaries;
- ulceration, bleeding, hyperemia;
- an increase in regional lymph nodes.
It is difficult to distinguish melanoma from a nevus by external signs, a doctor's examination is required
To determine the tactics of treatment, consultation of an oncologist and a surgeon is indicated.
Video
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Anna Kozlova Medical journalist About the author
Education: Rostov State Medical University, specialty "General Medicine".
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
