Congenital Melanocytic nevus of I.Randi

Generality

A congenital melanocytic nevus, by definition, is a melanocytic nevus present on the skin of the individual since birth.

More in detail, it is a melanocytic skin lesion that can occur on more or less extensive areas of skin. Depending on the type and size of the nevus, the clinical picture of the patient who manifests it may vary. If on the one hand, a congenital melanocytic nevus can have small dimensions and does not cause any concern, on the other hand, it is possible that at birth very high melanocytic lesions may occur which may expose the patient to risks to his health.

What is that

What is a Congenital Melanocytic Nevus?

As mentioned, a congenital melanocytic nevus - or melanocyte, if you prefer - can be defined as a nevus present on the skin of an individual from birth.

More in detail, it is a hyperpigmented skin lesion originating from melanocytes, the cells responsible for the synthesis of the melanin pigment. In detail, the congenital melanocytic nevus represents the consequence of a benign hyperproliferation of the aforementioned cells.

Despite the benign nature of the elevated melanocytic proliferation mentioned above, there is a risk that a congenital melanocytic nevus may evolve towards a malignant tumor (melanoma). This risk may be greater or less depending on the type of congenital melanocytic nevus manifested by the patient.

What is a congenital melanocytic nevus?

A congenital melanocytic nevus generally appears as a lesion of variable color from brown to black and with a rounded shape, sometimes ellipsoidal in shape. The margins may be more or less regular and the surface may or may not be covered with hair. However, the characteristics of a congenital melanocytic nevus may vary from patient to patient.

Types

Classification and Types of Congenital Melanocytic Nevus

The different types of congenital melanocytic nevus can be divided according to their size. Generally (but not necessarily), the greater the size of the skin lesions in question, the greater the risk of evolution towards a malignant form. However, based on the size of the lesion, it is possible to distinguish the following types of congenital melanocytic nevus:

• Small congenital melanocytic nevus: it is a melanocytic nevus whose size is less than 2 centimeters . Although it too, like any other type of nevus (congenital or acquired), is able to evolve into a malignant form, the risk appears to be lower than the types described below.
• Medium-sized congenital melanocytic nevus: it is a melanocytic nevus whose dimensions are between 2 and 20 centimeters in size.
• Giant congenital melanocytic nevus: a giant is defined as a melanocytic nevus whose dimensions exceed 20 cm in diameter. In the presence of a similar skin lesion, the risk of evolution towards a malignant form increases. In addition to this, the presence of a nevus of this size - which may increase with growth - can create aesthetic problems for patients who manifest them. The giant congenital melanocytic nevus appears as a large patch of very dark color, sometimes black. It can occur in any area of ​​the body, such as the back, belly and face, or it can involve multiple areas simultaneously. Often, moreover, in the vicinity of the melanocytic nevus in question there are other snows that are much smaller in size, but still dark in color and sometimes covered with hair: these are the so-called satellite nevi . Fortunately, the giant melanocytic nevus has a rather rare incidence.

Congenital Melanocytic Large Nevus VS Congenital Giant 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 speak of giant congenital melanocytic nevus, we refer to a hyperpigmented cutaneous melanocytic lesion whose size goes beyond 20 centimeters.

Macchia Mongolica

The Mongolian spot could, in a certain sense, be considered as a sort of congenital melanocytic nevus, even if, in medical language, it is more properly defined as " congenital dermal melanocytosis in the lumbo-sacral region ". However, the Mongolian spot is a bluish melanocytic skin lesion, characterized by irregular margins and variable dimensions that can exceed 10 centimeters in diameter. It owes its name to the fact that it manifests itself with greater incidence in individuals of Asian race.

Symptoms and Complications

Can Congenital Melanocytic Nevus Cause Symptoms?

In most cases, a congenital melanocytic nevus, regardless of its size, does not cause any type of symptom to the individual who manifests it, therefore, it is asymptomatic . However, if the nevus is not removed it can happen that, during the patient's life, it may give rise to symptoms such as discomfort and itching . The appearance of any symptomatology should prompt the patient to request a doctor's consultation, since while the aforementioned symptoms may not raise concerns, on the other hand they could represent, instead, the sign of a possible evolution towards complications.

Complications of Congenital Melanocytic Nevus

As repeatedly stated, the main complication of a melanocytic nevus consists in the evolution towards a malignant tumor form . In such a case it is possible to see the appearance of symptoms such as:

• Itching, discomfort and pain;
• Increase in the size of the nevus;
• Change in color and shape of the nevus;
• Alterations of the margins of the nevus;
• Nevus rupture and / or bleeding.

A congenital melanocytic nevus - like any other type of lesion, even if benign - should therefore always be kept under control, even more so if it is a medium-sized or giant melanocytic nevus. With regard to the latter type of congenital melanocytic nevus, it is again recalled that its presence may expose to a greater risk of evolution towards malignant tumor forms than it does for other types of congenital melanocytic nevi.

Furthermore, both the medium-sized congenital and nevus melanocytic nevus can create considerable aesthetic discomforts in the patient who, more often than not, can lead to reduced self-esteem and psychological problems .

When to worry?

Clearly, in the presence of a giant or otherwise large melanocytic nevus, the child should undergo a medical examination, even better if specialist, in order to make a correct diagnosis already during the first weeks of life. For the same reason, the performance of a specialist dermatological examination is advisable even in the presence of smaller congenital melanocytic nevi.

Later in the patient's life, if they are not removed, congenital melanocytic nevi must be kept under control.

However, in principle, it is necessary to worry when a congenital melanocytic nevus that has never caused discomfort gives rise to symptoms such as those reported above. The concern should be even higher when the aforementioned changes take place quickly.

Diagnosis

How is a congenital melanocytic nevus diagnosed?

For a correct diagnosis of congenital melanocytic nevus it is generally sufficient to carry out a specialist examination by a dermatologist. In addition to the simple observation of the nevus, the doctor can resort to the use of a special instrument to observe morphological aspects of the hyperpigmented lesion not visible to the naked eye: the dermatoscope .

Once the presence of a congenital melanocytic nevus has been diagnosed and after having assessed the type on the basis of size, the specialist can provide indications on how to proceed with the child's parents or the adult patient, as appropriate. In detail, it can recommend:

• Perform regular checks to monitor the evolution of congenital melanocytic nevus;
• Perform a biopsy to determine the nature of the hyperpigmented lesion;
• Proceed with the immediate removal of the congenital melanocytic nevus with consequent histological examination of the lesion removed to determine its nature.

The differential diagnosis must be placed against other types of acquired melanocytic nevi.

Care and Treatment

Treatments and Treatments to Eliminate a Congenital Melanocytic Nevus

Starting from the assumption that it is not always necessary to resort to the elimination of congenital melanocytic nevi, should this be necessary (for example, to avoid evolution in malignancy or because, due to size and location, the congenital melanocytic nevus creates psychological distress at patient) the only treatments currently available are those of a surgical nature.

Depending on the type of congenital melanocytic nevus to be removed, its size, its location and depending on the age of the patient (newborn, child, adolescent, adult, etc.), it is possible to use:

• Removal with classical surgery using a blade scalpel ;
• Surgical removal by electrosurgery ;
• Laser surgery ;
• Dermabrasion ;
• Skin expansion : this is a decidedly invasive technique which consists in inserting subcutaneously, in the areas not affected by the lesion but adjacent to the congenital melanocytic nevus, a special "expander" which is "inflated with physiological solution. Once the desired dilation is reached, the expander is removed, the congenital melanocytic nevus is surgically removed and "replaced" with the portion of dilated skin obtained through the action of the expander.

Clearly, the choice to use a certain method for the removal of congenital melanocytic nevus rather than another belongs only and exclusively to the specialist doctor, after performing a thorough examination and consequent correct diagnosis.