Generality
Melanocytic nevus is the generic term used to indicate different types of snow that can appear on the skin.
In detail, the melanocytic nevus is a hyperpigmented cutaneous lesion of a benign nature which, however, can evolve into a malignant form, thus causing the onset of skin tumors such as melanoma.
The melanocytic nevi currently known are many, each characterized by its own peculiarities that distinguish it from other types. However, despite this diversity, the treatment undertaken to eliminate them is generally one: surgical removal.
What is that
What is a Melanocytic nevus?
A melanocytic nevus is a hyperpigmented lesion originating from melanocytes, cells responsible for the secretion of the melanin pigment. More precisely, the melanocytic nevus is formed following a high proliferation - although benign - of the aforementioned cells.
In other words, this type of nevus - defined in the common language simply as " neo " - represents a pigmented skin lesion of the melanocytic type and of a benign nature.
Unfortunately, it is not possible to exclude a possible evolution of the melanocytic nevus into a malignant form. The possibility of this occurring depends on a set of factors, including the type of injury that develops on the patient's skin. In fact, the types of melanocytic nevus currently known are really many and can present a different level of risk for the development of malignant pathologies.
Classification
Classification of Melanocytic nevi
There are many types of classification that can be used to group the different types of melanocytic nevi existing.
A first great classification can be made according to the moment in which the melanocytic nevus appears. In this regard, it is therefore possible to distinguish:
- Congenital melanocytic nevus, ie present on the patient from birth.
- Acquired melanocytic nevus, that is a nevus that develops after birth, in the course of life.
Another widely used classification method involves the subdivision of the different types of melanocytic nevi depending on the place where the proliferative process that leads to the appearance of the lesion originates. In this case, therefore, it is possible to distinguish:
- Junctional melanocytic nevus: the proliferation of melanocytes that gives rise to the appearance of the nevus occurs at the level of the dermo-epidermal junction . The snows of this type generally have a rounded shape, a flat surface and take on a brown or blackish color. This type of injury tends to occur more frequently in childhood. Over time, the junctional melanocytic nevus may evolve to appear in relief, or it may regress.
- Dermal or intradermal melanocytic nevus : the proliferation of melanocytes occurs at the level of the dermis, therefore, below the epidermis. Melanocytic nevi of this type take on a color that varies from "skin color" to light brown and occur particularly during adulthood.
- Compound or combined melanocytic nevus: it is a particular type of melanocytic nevus that presents mixed characteristics between the junctional and dermal melanocytic nevus.
Other classification methods involve the subdivision of melanocytic nevi according to their structural characteristics, or again, depending on the body area on which they occur. However, these classifications will not be taken into consideration. In the next chapter, instead, the main types of melanocytic skin lesions will be briefly listed and described.
Did you know that ...
Freckles also fall into the large group of pigmented melanocytic skin lesions. However, in this article, this type of injury will not be analyzed. For more information on this, we recommend reading the dedicated article: Freckles.
Types of Melanocytic Nevi
As mentioned, melanocytic nevus is a generic term with which we want to indicate different types of pigmented skin lesions that originate from the proliferation of melanocytes. Therefore, the most known and widespread types of melanocytic nevus will be briefly described below.
Clark nevus
Also known as an acquired common melanocytic nevus, Clark's nevus is most probably the most widespread and known. It generally presents as a flat or slightly raised lesion in the center having a rounded shape. The color can be of various shades of brown, homogeneous or darker in the center and shaded on the sides. Generally located on the arms and on the trunk, it is a melanocytic nevus that appears mostly in adolescence.
Nevo by Clark Atipico
This type of nevus - also known as acquired atypical melanocytic nevus - has a rather high diameter (over 6 millimeters), irregular margins and non-homogeneous color. Being an atypical melanocytic nevus (that is, presenting irregular and uncommon features) it is considered as a lesion with a high risk of evolving into a malignant form and, for this reason, it must be kept under strict control (see: Mapping of the Nei).
Nevus of Unna
This type of melanocytic nevus appears as an acquired pigmented lesion which takes on a polypoid form and has a soft consistency ( papillomatous nevus ). The color of this nevus can vary from the color of the skin to the brown. The differential diagnosis should be placed against the pendulous or soft fibroids with which this melanocytic nevus could be confused.
Spitz nevus
The Spitz nevus is a melanocytic nevus that looks like a dome-shaped lesion whose color can vary from pink-reddish to brown-brown. It is a nevus that typically appears in the pediatric age and is generally characterized by a homogeneous coloring and a symmetrical shape.
Reed nevus
It is a melanocytic nevus that occurs in adulthood, particularly on legs and arms and with a higher incidence in female patients. The central part of this melanocytic nevus is dark brown or black and is surrounded by a series of radial stripes that give the lesion its classic "star" appearance .
Nevus of Miescher
It is another type of melanocytic nevus acquired in slow evolution that is generally manifested in puberty, usually in the face. The lesion is cupoliform, while the color may be brown or flesh-colored.
Sutton of Sutton
This melanocytic nevus is also known as " nevus with hypochromic halo ", as it is characterized by the presence of an area of hypopigmented skin that surrounds the actual nevus, usually reddish, or brown. The shape of the hypochromic halo reflects the shape of the surrounding melanocytic lesion.
Blue Nevus
It is a melanocytic nevus characterized by the typical blue-greyish or blue-blackish coloration. This color is due to the depth of the lesion in question. In fact, the melanocytes that proliferate giving rise to this type of nevus are located at the level of the dermis and hypodermis.
Meyerson nevus
It is an acquired melanocytic nevus also known as " nevus with inflammatory halo ". This is because the lesion is surrounded by an eczematous area . The nevus is normally characterized by regular shape and color; while the halo surrounding it tends to peel, especially in the outer area. Generally, this particular melanocytic nevus manifests itself in young adults, but it can also appear in old age.
Nevus of Ota
The nevus of Ota is an acquired melanocytic nevus with variable dimensions (from a few millimeters to a few centimeters) and a characteristic bluish color with blackish shades (melanocytes are located at the level of the reticular dermis ). It typically appears on the face - generally in the eye area - and can occur on both skin and mucous membranes.
Nevus of Ito
The nevus of Ito has characteristics very similar to the aforementioned nevus of Ota, however, it typically occurs at the level of the upper part of the shoulder.
Becker's nevus
The Becker nevus appears as a lesion with irregular margins with a brown color and the presence of numerous hairs inside it. To tell the truth, this is not a real melanocytic nevus, since - besides being formed by melanocytes - it also has a component deriving from smooth muscle fibrocells.
Macchia Mongolica
The Mongolian spot can be considered as a sort of congenital melanocytic nevus which, in medical language, is more properly defined as " congenital dermal melanocytosis in the lumbo-sacral region ". It is a bluish-colored lesion, characterized by irregular margins and variable dimensions that can even exceed 10 centimeters in diameter. The Mongolian bush should not be confused with the nevus of Ota, with the nevus of Ito or with the blue nevus.
Congenital Giant Melanocytic nevus
As you can easily guess from its very name, it is a congenital melanocytic nevus with very high dimensions (over 20 centimeters) and a characteristic dark, sometimes black pigmentation. Patients presenting this type of melanocytic nevus are more prone to the evolution of the lesion towards a malignant form (melanoma). Fortunately, the incidence is quite low; in fact, currently, the giant congenital melanocytic nevus is considered as a rare melanocytic hyperpigmented lesion.
Large and giant congenital melanocytic nevus
On the basis of size, some authors recognize a distinction between a large congenital melanocytic nevus (LCMN) and a giant congenital melanocytic nevus (GCMN). According to this distinction, the congenital melanocytic nevus is defined as large when the size of its diameter exceeds 20 centimeters; while it is defined as giant when the dimensions of the diameter exceed the 40 centimeters.
In most cases, however, when we talk about giant congenital melanocytic nevus, we are referring to a hyperpigmented skin lesion whose size goes beyond 20 centimeters.
Symptoms
Does Melanocytic Nevus Cause Symptoms?
In the vast majority of cases, the melanocytic nevus is completely asymptomatic . However, some types of snow may give rise to itching or a feeling of discomfort . In some cases, the appearance of such symptoms does not raise concerns, while in other situations the aforementioned symptomatology could represent the sign of an evolution towards a malignant form.
In such a situation, it is necessary to contact the dermatologist promptly, since this is the only figure able to make a correct diagnosis and establish whether it is appropriate to be alarmed or not.
When to worry?
When a melanocytic nevus that has never caused discomfort gives rise to symptoms of any kind, it is always good to undergo a dermatological examination.
The visit becomes even more necessary when - in addition to itching or discomfort - other symptoms appear and / or when the melanocytic nevus in question undergoes morphological alterations, such as:
- Alterations of the form to be regulated becomes asymmetrical;
- Modification of margins that become irregular;
- Color alterations;
- Increase in size;
- Appearance of pain and bleeding.
The concern should be even higher when the aforementioned changes take place quickly.
Did you know that ...
The appearance of itching or possibly discomfort - although it should not be underestimated under any circumstances - may not be considered dangerous when manifested in a melanocytic nevus not at risk of evolving into a malignant form.
In such a circumstance, therefore, it may not be necessary to intervene in order to eliminate the nevus. However, if the discomfort caused to the patient is significant, this may require removal to the dermatologist. This request can be made even if a melanocytic nevus - although asymptomatic and considered not at risk - due to its size and location, creates a certain aesthetic discomfort for the patient.
Clearly, the dermatologist always has the last word. In fact, only this health figure can and is able to establish which snow must be considered at risk and which is necessary and can be removed.
Diagnosis
How is a Melanocytic nevus diagnosed?
Generally, the dermatologist is sufficient to observe the melanocytic nevus to determine the type and to identify the presence of any anomalies.
The observation of the nevus is normally performed through the dermatoscope, an optical instrument that allows the dermatologist to observe morphological aspects of the melanocytic nevus that otherwise would not be visible to the naked eye.
If the dermatologist identifies suspicious or abnormal lesions, depending on the gravity of the situation, he can indicate to the patient different ways to go, such as:
- Perform regular checks to monitor the evolution of the melanocytic nevus in question (changes in size, shape, color, appearance of symptoms, etc.);
- Perform a biopsy to determine the nature of the pigmented skin lesion;
- Proceed with the immediate removal of the melanocytic nevus with consequent histological examination of the lesion removed to determine its nature.
In this regard, we recall once again that the choice to remove or not a melanocytic nevus must be taken only and exclusively by the dermatologist according to the characteristics of the nevus in question.
Treatments and Treatments
What treatments or treatments is it possible to use to eliminate a melanocytic nevus?
To eliminate a melanocytic nevus the only treatment available is surgical removal of the same.
Depending on the type of melanocytic nevus to be removed, its size, its depth and its location, it is possible to intervene through the use of different techniques, among which we recall:
- Dermabrasion (method used also in aesthetic medicine for the elimination of skin imperfections);
- Laser surgery ;
- Removal by electrosurgery ;
- "Classic" surgery using a blade scalpel.
Naturally, the choice of the method to be used for the removal of the pigmented skin lesion in question belongs exclusively to the dermatologist. Finally, after surgery, the removed melanocytic nevus will be subjected to histological examination.
