Mole or nevus, what is, what treatment?

1. Gastroepato
2. Dermatology
3. Mole or nevus, what is, what treatment?
4. The pimples, namely acne vulgaris

In general, the term can also be used in a broad sense, meaning any such chromatic or morphological alteration, localized and persistent, present on the skin surface.
All these reasons explain why, in scientific terminology, the word "nevus" is followed by an adjective that best defines it.

Eg:
if the nevus originates from the melanocyte (skin cells responsible for the production of melanin) then it is called melanocytic nevus;
if the nevus originates from keratinocytes, then it is called epidermal nevus.
if the nevus originates from pericitis, endothelial cells, then we talk about vascular nevi;
if the nevus originates from cells constituting the cutaneous appendages (in general, cells derived from the ectoderm), then one can speak of dermal nevi, sebaceous nevi, verrucous nevi, follicular nevi.

Melanomas, unlike the nevi, have asymmetry, irregular edges, color and diameter. See the photos below.

The melanocytes are cells that do not derive from the ectoderm, but from the neural crest, and that in their migration are then disposed in correspondence with the basal keratinocytes (of the dermo-epidermal junction), typically with a well established relationship, in general we have 1 melanocyte every 10 basic keratinocytes more or less.

The characteristic of these elements is that they are a little swollen and have a rather voluminous nucleus, easily recognizable also to the hematoxylin-eosin, round, sometimes with incisions, with a particularly evident nucleolus, with a conspicuous Golgi apparatus because they carry out synthesis and assembly of melanin, and within the cytoplasm there is the presence of granules (melanosomes) which are of various sizes but almost always roundish, more or less loaded with melanin.

In addition to this, they project a series of parallel or perpendicular dendritic projections to the basement membrane which interdigitate between the basal keratinocytes giving anchorage and trophism.

The melanocytes are subject to hyperplasia in the case of sun exposure by changing the ratio of before. Not only hyperplasia but also increase of melanosomes.

Histologically, along the basal layer are observed some cells a bit 'more rounded with a much larger nucleus and that have the characteristic halon just to make it clear that they are not a coating of the pavement epithelium but are attached, and therefore are a structure different from the original ectoderm.

Lesions of melanocytes

In normal skin, the melanocytes are distributed only in the basal layer of the epidermis and have subtle cytoplasmic extensions that branch out between the keratinocytes and make room for the skin surface. Melanocytes are responsible for the synthesis of brown pigment, melanin, which is then transferred to surrounding keratinocytes.

Melanocyte lesions can be distinguished in:
1. lesions that we can define benign - and that are however lesions of a proliferative type, therefore proliferations by the melanocytes but with a character of absolute benignity, for which the possibility of a malignant transformation is exceptional.
2. then frankly malignant injuries the most famous of which is melanoma,
3. and then there is an intermediate family (borderline) which is represented by the dysplastic nevus, we will see then in what is different from the other lesions. Often these have an eredo-family character and the recognition and their reclamation is useful to avoid the onset of a melanoma.

Benign lesions

We distinguish:
-the ephelidae, diffuse plaque (macula) lesions of a light color, generally non-persistent, particularly evident in the areas of photoexposure.
-the freckles are flat lesions (undetected), the patches that have the characteristic, even in the differences of size up to 3mm, to be persistent that is independent of the photo exposure, a hyperplasia of the melanocytes, and then we will have an increase at the portion junctional dermoepidermica of these melanocytes that configure, in fact, the freckle. Obviously we are talking about lentigo simplex.
- Benign nevuscytic (or melanocytic) nevi. They are for the most part of the acquired lesions that begin already in the childhood age, which are gradually developing and stabilizing and increasing around 30 years approximately.

-The Spitz nevus is characterized by being a benign tumor that, from the histological point of view, very reminiscent of a melanoma; in fact it grows rapidly in 6 months, but then stabilizes, is red, detected, papular, appears in children, in the areas of head and neck. Then there are some particular forms, the nevus of Ota, the nevus of Ito, we actually distinguish them only for a reason, due to the fact that these melanocytes have a characteristic location of the seat, in the nevus of Ota preferentially distributed at the level of the skin or mucous membranes in the territories of distribution of the first and second branch of the trigeminal, then maxillofacial area, the nevus of Ito has more or less equal characteristics, is always a cerulean nevus, bluish instead distributes to the acromio-deltoid region and are nevi intradermal in which the neurocytes are detected in the reticular dermis and therefore have a less intensely dark aspect. From the point of view of the possibility of malignant degeneration these snows do not cause concern. Obviously some of these snow cells, especially in the facial portion, can also be distributed to the labial mucosa or to the genital mucosa. These benign lesions, broadly, with the general characteristics, which are obviously the lesions of very large response in clinical practice.

The melanocytes can be classified into 9 clinical types:

Freckle: flat and dark pigment stain.
Acquired melanocytic nevus floor: flat or slightly detected pigmented lesion, symmetrical, with homogeneous pigmentation, with regular edges and with diameter <6 mm.
Atypical acquired melanocytic nevus: flat pigmented lesion or slightly detected, asymmetric, with inhomogeneous pigmentation, irregular edges and with a diameter> 6 mm.
Congenital melanocytic nevus: pigmented neoformation present at birth or forming after a few months. The dimensions are variable.
Nevus di Miescher: cupoliform lesion, acquired, light brown colored to the color of the skin. It occurs after puberty and is more frequent at the level of the face.
Neva di Unna: sessile or pedunculate neoformation with a papillomatous appearance and a soft consistency. It occurs after 30 years.
Nevi  of Spitz and Reed
Mongolian stain
nevus of Ota
nevus blu

Meaning of snows.
Snows are not conditions that can necessarily degenerate into melanoma, even if they are high, but only if they are dysplastic. They also have characteristics for which they are absolutely symmetrical lesions, and this is a very important clinical criterion of distinction, the other element is the absolute neatness of the margins.
The color can vary from rosé to true red, to copper, to light brown and to dark brown. Color that is homogeneous in benign nevus. However, there are achromic and hypochromic nevi and melanomas
From the ultrastructural point of view in the field of benign snow lesions, depending on the distribution of the cases, the nests of the snow cells, this distribution takes into account an element and that is where the lesions accumulate, where they go to place these nests of snow cells.
In the case of a neoplasia or meloma, the snow cells begin to aggregate no longer disposed to the interface line with the basal keratinocytes, no longer one occasionally but they appreciate blocks of these very close keratinocytes, perhaps for a stretch also quite extensive and are placed in the junctional region therefore there where the normal melanocytes already exist. But this is an opportunity and it is also, as we shall see, one of the opportunities to be held in high regard so much so that it is said that the junctional nevus is among these nevi snowy benign those that should be looked at with greater attention just for its intrinsic activity replicative.
Two other types of snow, the intradermal nevus, whose snows do not at all reach the basal keratinocytes, the dermal-epidermal interface, but are much deeper, are in the dermis, are intra-dermal, and clearly, we can guess, these they are the less pigmented nevi (bluish tends), because melanin is farther than the surface, they are the ones that have less dark color and the neuroses are deeply underrated. This is the effect of the path, of the migration that made the cells snow, we said descend along the projection of the neural crest to go to reach the dermo-epidermal junction, these stop before, in the intradermal site. They are the most trivial snows, which give us less worry. Also because being dermal it is less stimulated by UV rays. In intradermal nevus, on the other hand, there can be melanophages, histiocytes that are loaded with melanic pigment that is gradually released.
And it is clear, however, that if there is a deep, intradermal location, and if there is an orthotopic proliferation that is the junctional proliferation there will be a nevus in which there will be both components and therefore trivially, if there is a junctional component and if there is an associated intradermal component we will call it compound nevus, precisely because it brings these two aspects together.

The deep nevus that is marked by the starlet is much deeper while the junctional component always sees the individual elements so it is only an intradermal nevus and obviously the matched aspect (the compound nevus), ie, there are melanocytes both at the junction much more active, much more numerous, but there are also in the depth.
From the clinical point of view we can have nevi or sensed or verrucous planes. Very often these compound nevi have another characteristic: they take on a warty appearance, therefore apparently they look like a hyperkeratotic wart, they are then detected with respect to the cutaneous plane, often with a nodular "mammellon" aspect, often with hyperkeratosis on the surface, they simulate the wart however you see they rise up to form some detections and they have a double component, both junctional and deep intradermal, this is an absolutely peculiar characteristic of compound nevi. Sometimes they can take on a relationship with the hair bulb.

Much rarer and perhaps easier to recognize the so-called blue nevus. It is a caricatural aspect of intradermal nevus: that is, we have very deeply detected snow cells (intradermal nevus) so very far from the surface, this is why we call it "blue", because it seems a color much less accentuated than color dark of the nevus, and in reality this is also linked to the fact that these spills that are in the depth are spindled spindles so we are witnessing the dispersion, almost to the bluish striae that come from the subcutis, because these elongated spills what they do, distribute along this melted-cellular aspect, fusiform, their irregular melanosomes. And so this confers this characteristic aspect together with the fact that - also this is generally enough of the young - but it has a typical localization to the back of the hands and feet, an important element from the point of view of the clinical approach. But as you see, full-scale intradermal nevus, even if fusocellular, is the absolutely exceptional malignant transformation, as we have said is the norm of what happens in intradermal nevi. It is also not exclusive to the skin but also to the conjunctiva, where there are melanocytes that relate profoundly to the chorion, to their own tunic.

Then we have the congenital nevus. More rare. So far we have talked about these snows with their three varieties, we talked about snows that appear after birth and develop up to 30 years. They are however described, at birth, the nevi already present then congenital, and what is most interesting in this case - often associated with a proliferation pilifera around the nevus - is the size of these congenital snows: they can reach up to 20cm, to occupy an entire area of ​​the body, we talk about small congenital snows, medium, giant when they exceed 15-20cm in diameter, in this case this nevus which is a trivial nevus, a nevus composed with also an intradermal component, the only evolution malignant described is really responsible for these giant congenital nevi [to verify if the transformation can occur only in the giant congenital nevus], ie there would be a direct relationship between the possibility of the onset of a melanoma, this usually due to the fact that there is a greater quantity of melanocytes, and therefore the possibility that on different outbreaks may at some point establish a melanoma is directly proportional to the fact that being a nev congenito giant, if for example it was also in the photoexposed regions of course then undergoes' alteration, the actinic damage as we will see in melanoma, and in phototypes of a certain type, those with fair skin in particular, increases the risk of occurrence of a melanoma even if they are substantially rare events. Furthermore, transformation into melanoma is rare but it is possible and takes place at an early age. So follow-up is important.

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