Pigmented nevus: intradermal, borderline, complex

Such a formation on the skin, like a pigmented nevus, consists of an accumulation of melanocytes of different degrees of differentiation, which are located in different skin layers. In common parlance, a nevus is often called a mole, which is not entirely correct, since in many cases the neoplasm is not congenital, but acquired. Pigmented elements have a complex histological characteristic and are diverse in their clinical manifestations.[1]

Epidemiology

On average, there are approximately 20 pigmented nevi per unit of population in the world. In representatives of the white race, such formations are more common, and in people with dark skin color - less often. The total number of nevus elements may increase with age.

In babies of the first year of life, age spots are found only in 5-10% of cases. If a newborn child has a large neoplasm, then in the future he will have an increased risk of malignancy of the process. [2], 

In adolescents 12-15 years old, dermal nevus spots are more common, which are detected in 90% of cases.

In people aged 25-30 years, on average, there are up to 20-40 age spots on the body.

Causes Pigmented nevus: intradermal, borderline, complex

It is generally accepted that the tendency to form pigmented formations is inherited. Up to 1 in 10 cases of melanoma may be due to inherited defective genes [3]. However, in addition to the genetic factor, there are other reasons:

• radiation exposure;
• regular exposure to ultraviolet radiation;
• taking hormonal drugs (including contraceptive drugs);
• strong hormonal changes (puberty, pregnancy, menopause, etc.);
• regular use of products containing harmful synthetic components in their composition;
• the presence of bad habits that adversely affect the liver;
• various intoxications;
• immunodeficiency states or prolonged use of drugs that depress immune defenses.

Risk factors

Risk groups for the appearance of a pigment spot or protrusion include:

• persons whose professional activities are associated with prolonged exposure to ultraviolet rays, as well as with regular stay in the tropical and subtropical regions of the planet;
• people who regularly come into contact with various chemicals, ionizing radiation and electromagnetic radiation;
• people of light phenotype;
• patients with immunodeficiency conditions;
• people whose relatives have a large number of age spots on the body;
• persons who have been taking hormonal drugs for a long time;
• people who often injure the skin;
• women during pregnancy and breastfeeding;
• patients with endocrine pathologies.

Pathogenesis

The name "nevus" in Latin means "speck", "defect". A pigmented nevus itself is a benign pigmented outgrowth on the skin, which appears as a result of the accumulation of nevus cells. Such cells differ from other melanocytes in that they are devoid of processes, do not share melanin with nearby pigment cells, and have a slow metabolism.

Melanocytes during embryogenesis originate from the neural crest, after which they are transported to the area of their final localization point: to the skin, organs of vision, etc. Pigment cells are localized in the basal epidermal layer, near the zone of association with the dermal layer. From these structures, the cells of the pigment nevus develop.

New, acquired pigmented nevi are formed in a natural way, starting from the age of six months. The processes of formation of nevus growths are directly affected by hereditary predisposition, excessive ultraviolet radiation, etc. [4]

Symptoms Pigmented nevus: intradermal, borderline, complex

In most cases, a pigmented nevus has the appearance of a flat or slightly raised spot. The color scheme is different: from different shades of black and brown to grayish-blue. The contours are clear and even, the surface is smooth. The average sizes fluctuate within 5 mm. At the same time, larger specimens are often found - up to 10 mm and more. There are also cases of the development of giant nevi, which occupy extensive skin areas. In some patients, nevus formations may be covered with papillomatous and warty growths. Sometimes hair grows through the stain.

The borderline type of nevus looks like a nodule and has a dry, smooth surface without hair. The outlines are even, less often - wavy. The most common sizes are 2-4 mm. Slightly prone to enlargement and discoloration, but often multiple. The most common localization: soles, palms, genitals.

The blue type of nevus rises above the skin surface, can be hemispherical, with clear outlines and without hairline. Common localization: face, arms, legs, buttocks.

The risk of malignant degeneration increases dramatically if there are clinical signs of increased pigment spot activity. 

The first signs of possible malignancy

You need to be careful not to miss the early signs of a possible malignant degeneration of the pigment spot:

• acceleration of neoplasm growth;
• its seal;
• the appearance of asymmetry in any part of the growth;
• the appearance of itching, tingling, tension, pain;
• change in pigmentation (in any direction);
• the appearance of redness around the border of the pigment;
• disappearance of hair from the nevus surface;
• the occurrence of cracks, protrusions;
• bleeding.

If any of these symptoms, or a combination of them, is noted, you should definitely consult a doctor for adequate preventive and therapeutic measures. [5]

Pigmented nevus in a child

In newborn infants, these neoplasms are found relatively rarely, or are isolated. Upon reaching adolescence, such growths or spots are detected in almost every child, and by the age of 25-30 their number can reach several dozen.

Most of the congenital pigment elements found in a newborn baby are small and single, representing a defect in the development of melanocytes. With age, the congenital speck usually increases without causing discomfort. It is possible to suspect the degeneration of the process when there are signs of a disproportionate development of the neoplasm, or atypical changes.

According to external characteristics, children's nevus elements are divided into small (up to 1.5 mm), medium (up to 2 cm), large (more than 2 cm) and giant.

Acquired pigmented nevi begin their development from early childhood. Initially, a pigmented “dot” appears, approximately 1-2 mm in diameter. Over time, it thickens, a leg may form. The predominant localization of the spot is the upper body, head and neck. With the onset of puberty, the pigmented nevus often increases in size, darkens a little. New items are added frequently. In most cases, normal benign neoplasms do not increase to more than 0.5 cm in diameter, retain a uniform structure and color uniformity, contours, relief and symmetry.

In general, age spots change very slowly, over many months and even years, so they need to be monitored.

Stages

In its development, the pigment nevus goes through several stages, culminating in the processes of involution and fibrosis.

1. Border pigment nevus is characterized by the location of nevus structures at the border of epidermal and dermal tissue above the basement membrane.
2. A complex pigmented nevus includes histological manifestations of both intraepidermal and borderline formation. Nevus structures gradually extend into the papillary dermal layer. Accumulations of cells are also found in the dermis and epidermal layer.
3. Intraepidermal pigmented nevus is characterized by the localization of nevus structures only in the dermis. This is the final stage of the development of this neoplasm. In the course of deepening into the dermis, the structures lose their ability to synthesize melanin. As a result, the growth loses pigmentation. That is why the intraepidermal nevus is depigmented in most cases.

Forms

• Congenital pigmented nevus is of the following types:
  • Spotted nevus, which has the appearance of a light brown spot 10-150 mm in diameter, contains dark brown spots or papular formations on its background.
  • Pigmented melanocytic nevus - found in 1% of infants, while 1 out of 500 thousand newborns has a giant pigmented nevus. In some cases, the neoplasm appears only a few weeks after the birth of the child. There is a preservation or loss of the skin pattern: when the pattern is lost, this means that the cellular structures have penetrated into the reticular layer of the dermis with the formation of a deep congenital melanocytic element.[6]
  • Linear nevus refers to congenital ectodermal anomalies. It is characterized by the appearance of pigmented papules localized on Blaschko's lines.

• Acquired pigmented nevus can manifest itself in the following varieties:
  • Blue nevus - has the appearance of a papule or nodule of blue-dark color. Histology demonstrates focal melanocytic intradermal proliferation. In turn, there are three types of blue nevi: ordinary, cellular and mixed pigmented nevus.
  • Setton's nevus (also known as halonevus) is a melanocytic formation surrounded by a hypopigmented halo. The main factor in the appearance of build-up is considered to be regular trauma and excessive insolation. Spontaneous depigmentation is not excluded.
  • Myerson's nevus - has an eczematous rim around the circumference of the neoplasm.
  • Ophthalmomaxillary nevus - characterized by impaired pigmentation in the area innervated by the ophthalmic and maxillary nerve. The growth contains melanin-enriched melanocytes, which have processes and are localized in the upper zone of the dermis.
  • A dysplastic pigmented nevus consists of proliferating atypical melanocytes and is an irregularly shaped speck or plaque growth with a fuzzy outline of a brownish or dark hue.

There are a number of pigmented neoplasms that can be either congenital or acquired. One example is papillomatous intradermal pigmented nevus, which has much in common with ordinary papilloma. This is a benign element, often brownish, brownish or pastel in color, it is able to begin its development at almost any age, from the neonatal period to old age. Papillary pigmented nevus is often large, most often found in the head or back of the neck.

Intradermal, intradermal pigmented nevus is the most common type of pigmented neoplasms. It is formed in the deep dermal layers, rises above the surface of the skin, has a domed configuration, and is sometimes covered with hair. More often, its base is wide, but there are also elements on the stem. The neoplasm is benign, but with frequent damage it can transform into a malignant tumor.

Unilateral pigmented nevus - congenital or acquired - is localized along the lines of Blaschko, which correspond to the directions of migration and proliferation of mutant cell structures in the process of embryonic development. Other names for a unilateral neoplasm: linear, segmental, blastcoid, blastcolinear.

In addition to the above classification, there are single (single) and multiple pigmented nevi, as well as various growths depending on their location:

• Pigmented nevi of the face are often located in the forehead or cheeks, less often on the temples and lips. Such neoplasms should be removed especially carefully, since the skin on the face is quite sensitive and thin. A pigmented nevus on the lip is subject to mandatory removal, which is associated with frequent trauma to the element and a high risk of malignancy.
• Pigmentary nevus of the choroidal eye is almost always localized on the posterior surface of the fundus, so it cannot be seen with the naked eye. A neoplasm can be examined with the help of an ophthalmological examination, or if it is located in the equatorial zone of the eye. The pathological element looks like a slightly prominent growth of a grayish tint, with clear outlines and dimensions of about 5 mm.
• A pigmented nevus of the conjunctiva appears inside or outside the mucous membrane of the transparent membrane of the eye. The most common localization is the corner of the upper part of the eyelid or the corneal margin. The neoplasm is usually flat, with clear edges and about 3-4 mm in size. Pigmented nevus of the iris, like the conjunctiva, is well seen with a slit lamp.

Complications and consequences

According to experts, a pigmented nevus can degenerate into melanoma under the influence of various risk factors, among which traumatic damage to the growth dominates. Although in some cases, melanoma can develop without previous trauma.

The actual frequency of malignancy of neoplasms has not been precisely established to date. Experts note that not every case of nevus growth ends with the development of a malignant process. For this reason, benign spots are classified as facultative pre-malignant skin formations that do not necessarily regenerate, but have certain risks. Such types of nevus growths as complex, borderline, giant, blue and intradermal have a special tendency to malignancy.

The multiplicity of pigmented nevi is considered an increased risk factor for the development of melanoma.

It is now well established that giant congenital nevi and malignant melanoma are related, although the magnitude of the risk of malignant transformation is still the subject of much debate. Widely divergent figures range from 1.8% to 45%. A recent review [7]estimated that the incidence of melanoma in nevi larger than 2% of total body surface during the first 15 years of life is 8.52%.

Diagnostics Pigmented nevus: intradermal, borderline, complex

Most often, the diagnosis of nevus formations consists in examining the surface of the body by a dermatologist. The specialist will pay attention to the shape, structural uniformity, color scheme, location, hair growth, after which he will make a diagnosis and describe further actions.

In some cases, the diagnosis is controversial or ambiguous, so the doctor has to resort to additional diagnostic methods. A micropreparation and its cytological examination are rarely used, since during the taking of the biomaterial, the neoplasm is injured, which increases the risk of malignant degeneration. A similar study can be used if there are cracks, weeping, wounds and sores in the area of the pigment spot.

A safer method is considered to be luminescence microscopy, reflective confocal microscopy  [8], spectroscopy  [9] and computer diagnostics, which involves obtaining an image of a spot with its further characterization. 

Laboratory tests are prescribed to determine the likelihood of transformation of the growth into a malignant tumor. To do this, the patient donates blood for tumor markers - specific antigen proteins that are formed and released into the blood in the presence of a tumor process.

Instrumental diagnostics is most often represented by a histological examination, which helps to determine the type of pigmented nevus, the stage of its development, and the likelihood of malignancy. A macropreparation is obtained during the removal of the neoplasm and is immediately sent for diagnosis, where it is pre-treated and microscopically examined.

According to the results of the histological examination, the specialist determines the typical affiliation of the pathological element, in accordance with the cell morphology. The thickness of the growth is measured in micrometers by measuring the longest diameter from the top of the element to the lowest (deep) tumor cell.

Pathoanatomy of the biomaterial is important for differentiating the pigmented nevus and determining further treatment tactics (if necessary). The description should take into account the following factors:

• histological affiliation;
• neoplasm thickness;
• the presence of ulcers;
• marginal resection fields.

When melanoma is detected, the doctor draws up a pathomorphological report and draws up an individual further treatment plan.

Differential diagnosis

Pigmented nevus must be distinguished among many types of neoplasms on the skin, which are both absolutely safe and life-threatening for the patient.

So, you need to consider the likelihood of developing the following skin elements:

• Benign (atheromas, lymphangiomas, papillomas, hemangiomas, lipomas, moles and nevi, fibromas and neurofibromas).
• Malignant (basaliomas, sarcomas, melanomas, liposarcomas).
• Precancerous or borderline skin elements (xeroderma pigmentosa, senile keratoma, cutaneous horn).

Nevus elements are often called by other terms - for example, moles, nevoid formations, birthmarks, etc. A mole or a pigmented nevus are considered equivalent concepts when it comes to a congenital neoplasm.

Treatment Pigmented nevus: intradermal, borderline, complex

The tactics of treating pigmented nevi is selected individually, but in most cases it is a radical removal of the neoplasm without the use of any kind of traumatic techniques (for example, chemical burning). The most common removal methods are:

• Surgery is a reliable method that does not require expensive equipment and can be used for any nevus variations. However, surgical treatment also has some disadvantages: for example, quite noticeable scars can remain after the operation. Most often, this method is used if it is necessary to remove a large pigmented nevus, or a suspicious neoplasm with signs of malignancy.
• Laser removal of pigmented nevi is recommended for small formations located on any part of the body, including the face. The procedure is painless, the problem disappears almost without a trace, but the method is not recommended for large nevi. [10]
• The cryodestruction method can be used to remove small surface spots. Cryodestruction involves exposure to liquid nitrogen: in contact with a temperature of -196 ° C, the cells are frozen, the growth is destroyed, a crust is formed, which subsequently disappears. The procedure is painless, there are practically no scars.
• The method of electrocoagulation is opposite in effect to cryodestruction and involves exposure to high temperatures. The coagulator loop is heated to a certain temperature mark and the tissues are cauterized, separating the healthy tissue from the pathological focus. The advantages of this method are the elimination of bleeding, but the procedure is somewhat painful, so local anesthesia is required.
• The method of radiosurgery is to use high-frequency radio waves. Removal of age spots occurs in a non-contact way, and the procedure itself is painless and safe.

Which method of removal will be used is decided by the doctor in each specific situation, taking into account the size, type, and probability of malignancy of the pathological element.

After the procedure to remove the neoplasm, the doctor prescribes a restorative treatment. The following external medicines are used:

• A solution of potassium permanganate of low concentration. To prepare the solution, take 100 ml of pure boiled water, add a few crystals of potassium permanganate to it, mix thoroughly until it is completely dissolved. The tool is used for accurate treatment of the wound 2 times a day. A weakly concentrated solution (2-5%) does not cause additional tissue irritation, but has the necessary antibacterial, drying and deodorizing effect.
• Levomekol ointment is an anti-inflammatory and antibacterial drug that is prescribed for external application daily for 4 days. If after the first day of using the ointment an allergic reaction develops, then further use of the drug should be discontinued.
• Propolis tincture is a natural preparation that promotes wound healing. Topically applied in the form of applications or washes, twice a day for 5-6 days. In standard dosages, the tincture is non-toxic and well tolerated by patients.
• Brilliant green alcohol solution is a well-known antiseptic and disinfectant that should be applied to the edges of the wound surface twice a day. At the time of treatment, a slight burning sensation may occur, which quickly passes. Allergic reactions are rare.

Subject to all the recommendations of the doctor, the wound heals quickly after removal of the pigment spot, leaving a small scar or depigmented area, which smooths out over time.

Prevention

A benign pigmented nevus does not pose a health hazard. The only risk is that the pathological neoplasm has a tendency to malignant degeneration. To prevent this from happening, it is necessary to keep the condition of the pigment spot under control, observe its changes, and avoid injury. Doctors provide the following recommendations in this regard:

• before going for a walk in sunny weather, you should use sunscreen or cover exposed areas of the body with clothing;
• you should not abuse the tan, including the solarium;
• it is undesirable to apply aggressive cosmetic procedures to the skin that can damage and injure tissues;
• if even the slightest suspicion of the formation of a malignant element appears, you should immediately consult a doctor.

If there are already pigmented nevi, then you don’t need to worry too much, but you shouldn’t let the situation take its course either. It is enough to periodically visit a dermatologist or oncologist to monitor the formation. If the doctor considers it necessary, he will prescribe surgical or alternative removal of the problematic growth.

Despite the controversy, many clinicians agree that prophylactic removal of all giant and large hairy nevi is indicated.[11]

Forecast

Absolutely all age spots and dots on the skin require constant monitoring. Particular care and attention should be exercised in relation to neoplasms located on traumatic parts of the body, as well as to previously damaged, regularly growing and intensively changing nevus elements.

With the timely removal of a suspicious or poorly located pigmented nevus, the prognosis is completely favorable.

If the patient refuses radical treatment of the formation, or its removal is not possible due to the difficulties of the anatomical location, then it is necessary to strictly follow the medical recommendations: exclude possible damage to the pathological growth, protect it from sunlight, regularly visit a dermatologist-oncologist.

With malignancy of the pigmented growth, the prognosis depends on its size and location, the degree of prevalence in the lymphatic system, the presence and number of metastases. The earlier a malignant tumor is detected, the better the prognosis will be. The survival rate at an early stage of detection is 90-95%. The five-year survival rate for plantar melanoma is 82% for lesions up to 1.49 mm and 0% for lesions larger than 3.5 mm. [12]

Most nevus forms do not pose a danger to human health and life if they are not damaged, rubbed, irritated and protected from ultraviolet radiation.

Pigmented nevus and the army

In the vast majority of cases, in the presence of nevus neoplasms, the conscript is not exempted from military service. However, sometimes a young man can still be exempted from conscription with the assignment of the category “limited fit” or “unfit for service”. This is possible:

• if we are talking about a large benign growth, which is “unfortunately” located on the body, and presumably will interfere with the wearing of military uniforms and equipment, provided that it cannot be removed (there are contraindications confirmed by a doctor);
• if malignancy is confirmed.
• In order to find out whether they will be taken into the army with a nevus growth, a young man should:
• visit a therapist, dermatologist and oncologist for a consultation;
• collect the necessary certificates confirming the presence of a pathological formation;
• provide a medical card with a confirmed diagnosis and the conclusion of doctors.

Pigmented nevus often requires increased attention to it and regular monitoring of the condition. Therefore, there is every chance to prove the need for systematic medical supervision and the impossibility of military service - again, provided that there are contraindications to the removal of the pathological element.