Nevi: causes, symptoms, diagnosis, treatment

Blue nevus

The cause of the disease is unknown. It usually occurs in women.

Symptoms. Characteristic appearance of small, point, spotted or spotty-papular elements of a round shape from several millimeters to 1 cm in diameter, dark blue in color. This is due to the Tyndall effect and is associated with the deep location of melanin in the dermis.

The rash elements are usually localized on the face, neck, back of the hands and feet, buttocks, and less often on the mucous membranes.

May transform into melanoma in old age. Ulceration and bleeding are not typical. Sometimes multiple eruptive blue nevi are found.

Histopathology. In the dermis, spindle-shaped and dendritic cells containing melanin in the form of large, clearly distinguishable granules are determined. Proliferation of fibroblastic cells is noted.

Treatment: Surgical excision is performed.

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Nevus of Sutton

Synonyms: halo nevus, bordered nevus

Sutton's nevus is a nevocellular nevus surrounded by a depigmented rim.

Causes and pathogenesis. The disease may be based on autoimmune disorders, i.e. the appearance of cytotoxic antibodies in the blood and the action of cytotoxic lymphocytes. In the depigmentation focus, a decrease in the melanin content in melanocytes and the disappearance of the melanocytes themselves from the epidermis are noted. It occurs equally often in both men and women. Vitiligo is often present in the family history.

Symptoms. Before the appearance of a halo nevus, there is slight erythema around the nevocellular nevus. Then a round or oval lesion is formed - a brown or dark brown papule with a diameter of about 3-5 mm (nevocellular nevus), surrounded by a clearly defined depigmented or hypopigmented rim. Such a halo nevus occurs on any part of the body, but more often on the trunk. Subsequently, the nevocellular nevus may disappear. Halonevi may disappear spontaneously.

Differential diagnosis. The disease must be differentiated from blue nevus, congenital nevocellular nevus, Spitz nevus, primary melanoma, common wart and neurofibroma.

Treatment. In case of an atypical clinical picture and doubts about the diagnosis, the nevus is subject to excision.

Spitz nevus

Synonyms: Spitz nevus, juvenile nevus, juvenile melanoma

The disease occurs at any age. About a third of patients are children under 10 years old. After 40 years, the disease is rare. 90% of nevi are acquired. There are reports of familial cases.

The causes and pathogenesis of the disease are unknown.

Symptoms. On the skin of the head and neck there is a papule (or node) with clear boundaries, round or dome-shaped, with a smooth surface, devoid of hair, less often - hyperkeratotic, warty. Its size is usually small - less than 1 cm. The color of the tumor-like formation is brown, the color is uniform.

On palpation, the nevus is noticeable. In rare cases, bleeding and ulceration are possible.

Histopathology. The tumor-like formation is located in the epidermis and reticular layer of the dermis. There is hyperplasia of the epidermis, proliferation of melanocytes, dilation of capillaries, a mixture of large epithelioid and large spindle-shaped cells with abundant cytoplasm, and some mitoses.

Differential diagnosis: Spitz nevus should be distinguished from malignant melanoma of the skin.

Treatment: Surgical excision with mandatory histological examination is performed.

Becker's nevus

Synonym: Becker-Reiter syndrome

The causes and pathogenesis of the disease are unknown. Men are 5 times more likely to get sick than women. Family cases of the disease are possible.

Symptoms. The disease begins in puberty with the appearance of a single plaque with an uneven, slightly warty surface. The color of the lesion is from yellow-brown to brown, the color is uneven. A large plaque of irregular shape, with jagged borders is localized on the skin of the shoulders, back and forearms, under the mammary glands. In the lesions, increased growth of terminal hair is noted. On the part of other organs, shortening of the upper limbs or underdevelopment of the chest may occur.

Histopathology. Acanthosis, hyperkeratosis, and rarely, horn cysts are observed in the epidermis. Nevus cells are not detected. The number of melanocytes is not increased. Increased melanin content is visible in the keratinocytes of the basal layer.

Differential diagnosis: Becker's nevus must be distinguished from McCune-Albright syndrome and giant congenital nevocellular nevus.

Treatment: There is no specific treatment.

Epidermal nevus

Causes and pathogenesis. The onset of the disease is associated with dysembryogenesis. Familial cases are noted.

Symptoms. The disease usually exists from birth: there are oval, linear or irregular warty, hyperkeratotic papillary formations of various localizations, which are often located unilaterally.

Histopathology: Hyperplasia of the epidermis, especially of the appendages, and sometimes vacuolization are noted.

Treatment: Cryotherapy, electrocoagulation, carbon laser, aromatic retinoids are used.

Nevus of Oto

Synonym: gray-blue oculomaxillary nevus

Causes and pathogenesis. The causes remain unclear. The pathology is considered hereditary. It is inherited autosomal dominantly. Some authors consider the nevus of Oto as a variant of the blue nevus. It is more often found in people of Asian origin (Japanese, Mongolians, etc.), as well as in people of other nationalities.

Symptoms. Nevus Oto may develop from birth or appear in childhood, women are more often affected. The clinical picture of the disease is characterized by a unilateral change in skin color in the innervation zone of the first and second branches of the trigeminal nerve (skin of the forehead, around the eyes, temples, cheeks, nose, ears, conjunctiva, cornea, iris). The color of the lesions varies from light brown to gray-black with a bluish tint. Their surface is smooth, does not rise above the skin level. The sclera is often colored blue, the conjunctiva - brown. The boundaries of the lesion are irregular, blurry. Vision is usually not affected. Over time, the intensity of the color weakens. Spotted rashes can also be located in the lip area, oral cavity (soft palate, pharynx), on the nasal mucosa. Cases of degeneration into melanoma as a result of irritation of the nevus, combination with nevus of Oto and bilateral location of the lesion have been described.

Histopathology: Characteristic presence of dendritic melapocytes between collagen fiber bundles.

Differential diagnosis is carried out with other pigmented nevi.

Treatment. There is no specific therapy. Regular follow-up with a dermatologist and ophthalmologist is necessary.

Congenital nevocellular nevus

Synonyms: congenital pigmented nevus, congenital melanocytic nevus

The disease is congenital, although rare varieties appear during the first year of life. Men and women are equally affected.

Causes and pathogenesis. Congenital nevocellular nevus occurs as a result of a disorder in the differentiation of melanocytes.

Symptoms. There are small, large and giant congenital nevocellular nevus localized on any part of the skin. Nevi are soft to the touch, pliable, their surface is bumpy, wrinkled, folded, lobed, covered with papillae or polyps, resembling brain convolutions. The color of the lesions is light or dark brown. The shape of small and large nevi is round or oval, and giant ones occupy an entire anatomical area (neck, head, trunk, limbs). With age, they can increase in size, and perineus vitiligo may develop.

Treatment: Given the risk of localization, surgical removal is desirable.

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Systematized pigmented nevus

Symptoms. Systematic pigmented nevi can be congenital or acquired. They can occur in utero and under the influence of various injuries, infectious or other general diseases of the mother.

In congenital systematized pigmented nevus, symmetrical flat or slightly raised above the skin level spots of yellow-brown color appear, often scattered over the entire skin. These spots are sharply demarcated from the intact skin and have no inflammatory changes at the periphery.

The lesions sometimes merge to form large areas of hyperpigmentation with unclear boundaries. They are most often located on the neck, in the area of natural folds, and the torso. The skin of the face, palms, and soles, as well as the nail plates, are often free of lesions. There are no subjective sensations.

Differential diagnosis: The disease should be distinguished from urticaria pigmentosa, melanosis cutis, acquired lentigines and Addison's disease.

Comedonic nevus

The causes and pathogenesis of the disease are unknown.

Symptoms. Comedonic nevus is a rare variant of nevi, clinically manifested by a lesion, within which there are closely grouped follicular papules, slightly elevated above the skin surface, the central part of which is saturated with a dense horny mass of dark gray or black color. When the horny plug is forcibly removed, a depression is formed, in the place of which atrophy remains.

Nevus can be congenital or acquired. The lesions often have a linear configuration and can be located unilaterally or bilaterally. Nevus can appear on any part of the body, including the palms and soles. The lesions are usually asymptomatic, without subjective sensations.

Histopathology. Histologically, comedone nevi reveal invaginations of the epidermis filled with horny masses, into the lumen of which ducts of atrophic sebaceous glands or hair follicles may open. A pronounced inflammatory reaction in the dermis is characteristic.

Differential diagnosis: The disease should be distinguished from porokeratosis of Mibelli, a papillomatous malformation.

Treatment: Electroexcision is often used.

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