In most pigmented pathologies, the point of application of the therapeutic effect is melanosomes in melanocytes or melanocytes themselves, less often it is melanosomes in keratinocytes. In some cases, the spread of thermal injury from pigmented melanocytes may be beneficial, as leads to damage to adjacent melanocytes with insufficient melanin content to effectively remove melanin (for example, dermal nevus or complex melanocytic nevus).
MD, Professor, Honored Doctor of Ukraine,President of the Ukrainian Society of Aesthetic
Medicine, General Director of the Ukrainian
Institute of Plastic Surgery
and aesthetic medicine "Virtus"
Depending on the layer of the skin in which most of the pigment is located, epidermal, dermal and mixed (having both dermal and epidermal components) pigment pathologies are distinguished:
epidermal - lentigo, cafe-au-lait spots, ephelids, nodular nevus, nevus spilus and seborrheic keratosis;
- dermal – blue nevus, nevus Ota and nevus Ita;
- mixed – melasma, Becker's nevus and complex melanocytic nevus.
- This classification includes both neoplasms and non-neoplastic pigment deposits.
The greater the pigment depth, the longer wavelength laser should be used.
The tactics of removing pigmented neoplasms is the same as for other types of benign skin neoplasms: epidermal and intradermal neoplasms with a diameter of up to 5 mm are removed with a pulsed vaporizing laser, and pigment deposits, regardless of the depth of occurrence – pulsed non-ablative lasers with a wavelength of 600-800 nm (ruby, alexandrite, diode lasers, Nd:YAG).
Benign nevi
Simple acquired non-cellular nevus (birthmarks)
Acquired non-cellular nevi are conditionally classified into the following types depending on the localization of nevus cell clusters:
borderline non-cellular nevus – nevus cells are located on the border of the epidermis and dermis above the basement membrane;
- complex (mixed) neocellular nevus – combines histological signs of borderline and intraepidermal nevi, nevus cells gradually penetrate into the papillary dermis; their accumulations can be found both in the epidermis and in the dermis;
- intradermal non-cellular nevus – nevus cells are located only in the dermis, this is the last stage of development of a non-cellular nevus, as they sink into the dermis, nevus cells lose their ability to synthesize melanin, and the nevus loses pigmentation, so intraepidermal nevi are almost always pigmentless.
- Borderline non-cellular nevus is removed without leaving a trace using an ablative CO2 or Er:YAG laser. Complex and intradermal nevi up to 5-8 mm in diameter, if indicated, can be vaporized, the end result will be a small scar of the same size.
For diameters of 1 cm or more, surgical removal is recommended, but resection margins may be minimal (Fig. 2.5-12). When using non-ablative pulsed lasers, the treatment efficiency varies greatly from patient to patient, persistent lesions and relapses are common, but the side effects are minimal.
Nevus Spitz (epithelioid and spindle cell nevus, juvenile nevus, juvenile melanoma)
Treatment: it is advisable to surgically excise the neoplasm before the end of puberty, and the distance from the edge of the nevus to the borders of the resection is at least 5 mm. However, due to the frequent localization on the face, after performing the full range of diagnostic measures, it is possible to perform laser vaporization of the nevus in order to ensure the maximum cosmetic effect.
A non-cellular nevus surrounded by a halo of hypopigmentation. The cause of depigmentation is a reduced content of melanin in melanocytes or the disappearance of melanocytes from the epidermis.
Halonevus does not require treatment, it resolves on its own, while the pigmentation of the peripheral rim is restored last. Does not transform into melanoma.
The only melanocytic skin neoplasm that has no connection with the epidermis and is localized in the dermis, the bluish color is due to the deep occurrence of the melanin pigment in the skin. , change in its appearance) surgical excision with subsequent histological examination is recommended. Rarely, a blue nevus transforms into melanoma.
Nevus Ota
It is a violation of pigmentation in the zone of innervation of the ophthalmic and maxillary nerves. It consists of melanin-rich melanocytes that have processes and are located in the upper part of the dermis. The nevus of Ito has the same clinical and histological features as the nevus of Ota, but is localized in the neck or shoulder. Nevus Ota is much less common.Nevuses are benign in nature, but rare cases of malignant melanoma are known.
Dynamic observation is recommended, treatment is not carried out without indications. Indications for laser vaporization are the same as for other pigmented neoplasms.
Spotted nevus (scattered, spilus)
It is a light brown spot, on the background of which there are dark brown spots or papules. Dark patchy areas represent borderline or complex non-cellular nevi or, rarely, dysplastic nevi. As a rule, a spotted nevus does not change throughout life and does not need special treatment. Laser removal is most often performed in cases where the patient perceives it as a cosmetic defect.
Nevus “coffee with milk” (spots café au lait, CALMs)
This is a light or dark brown, irregularly shaped spot that has clear boundaries. There is no threat of malignant degeneration of these nevi; most cases of treatment are cosmetic in nature. Treatment – vaporization, with a significant size of the nevus, preference is given to the Er: YAG laser (to prevent significant thermal damage). Relapses are possible, even after a long time, but they are usually easy to repeat therapy.
Nevus Becker
Becker's nevus, or Becker-Reiter's syndrome, pigmented hairy epidermal nevus, Becker's melanosis is characterized by an area of hyperpigmentation and hypertrichosis, usually located on the shoulders and in the back. There is no risk of degeneration into melanoma.
Often no treatment is required. In the presence of a significant aesthetic defect, surgical excision or laser vaporization is performed. With localization on the face and intradermal location of the neoplasm, it is possible to effectively use a combination of ablative and non-ablative lasers: after vaporization of the epidermal part of the neoplasm, its intradermal part is destroyed using one of the nanosecond lasers. The problem of increased hair growth is solved with a diode laser (810 nm) (Fig. 2.5-13).
Non-neoplastic pigmented skin lesions
It is a flat dark brown spots formed as a result of the proliferation of melanocytes, does not contain nevus cells. Lentigo is youthful and senile (senile, sunny), is not a precancerous skin lesion.
Often no treatment is given. If the patient perceives lentigo as a cosmetic defect, it is possible to use nanosecond lasers (the most effective is ruby, 680 nm). When age-related lentigo is combined with other age-related skin changes, laser resurfacing of the facial skin is preferable, in which wrinkles, lentigo and other age-related neoplasms are eliminated in a complex (Fig. 2.5-14).
Ephelids
For cosmetic purposes, these formations are treated with nanosecond ruby or alexandrite lasers. Exposure to ultraviolet light causes a recurrence of the problem and the appearance of new ephelids.
Melasma
Acquired slowly developing symmetrical hypermelanosis on the face is an external manifestation of hormonal changes in a number of gynecological diseases and pregnancy. Histologically, there are two types of melasma. In the epidermal type, the main deposits of melanin are located in the basal and suprabasal layers. The dermal type is characterized by the presence of melanophages in the superficial and deep layers of the dermis, as well as hyperpigmentation of the epidermis.
Forms with surface components are better treated with shortwave lasers (KTP, 532 nm; copper vapor, 511, 578 nm; dyes, 575-600 nm), and formations with dermal components – long-wavelength lasers (alexandrite, 755 nm; ruby, 680 nm), due to less scattering of long waves. When melasma is combined with other age-related skin changes, laser resurfacing of the facial skin is advisable.
To be continued.
Source estet-portal.com
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