Naevus

NAEVUS, birthmark (syn.: mole, naevus maternus), a congenital developmental anomaly of the skin in the form of persistent spots or tumors. Naevi are usually congenital, but can also develop after birth, more often during sexual maturity, and rarely later—N. tardus (Fournier), sometimes following a general acute infection, such as typhus, influenza, etc.—N. infectivus (Hutchinson) or postinfectiosus (Gougerot). The boundaries of the "naevus" group are very uncertain and conditional: some authors include almost all benign neoplasms, especially those arranged in groups or linearly; others narrow it to some extent. Darier, for example, distinguishes 4 forms of birthmarks: 1) flat-pigmented N., 2) verrucous pigmented N., 3) adenomatous pigmented N., 4) vascular N. Flat pigmented N. (N. pigmentosus). Their clinical picture is diverse. Color ranges from light-brown, coffee-with-milk color, brown to saturated black. The surface is smooth, at the same level as the skin (N. planus) or slightly elevated (N. elevatus, lentigo).- Verrucous pigmented N. are divided into 2 groups: soft and hard; the first group includes common verrucous N. (N. verrucosus, s. papillaris), in other cases covered with hair (N. pilosus), the second group includes birthmarks covered with abundant layers of horny scales and in some cases resembling ichthyosis (Naevus ichthyosiformis) or a verruca. In all these forms of pigmented N., the size of elements varies—from a millet seed to the palm of the hand and significantly larger. The number of elements is very diverse—from one to many dozens (see separate table (pp. 135-136), figure 5). The location is usually random, although there are cases when the location of elements is systematic, for example a naevus occupies half the body, asymmetrically located on one half or symmetrically in the form of a cloak or corset; in other cases it is located as if along the course of a nerve (Nervennaevi, ichthyosis linearis neuropathica) or, which is more often observed, in the form of lines (p. linearis). Once appeared, N. increase in size along with the growth of their host and exist until the end of their life; in very rare cases pigmented N. can regress, leaving depigmentation (Pospelov). Pigmented verrucous N. can undergo malignant transformations, which begin with the appearance of limited melanosis and then progress to naevo-carcinoma. Some authors (Brocq) include molluscum-like N. (molluscum pendulum, fibroma molluscum, n. mollusciformis) in this group, which are usually found in large numbers in adenomatous N. (so-called adenoma sebaceum) and Recklinghausen's disease. Clinically, these are brown-colored fibromas, ranging from the size of a pea to a pinhead, attached to the skin by a thin stalk. Histology. In pigmented N., both flat and verrucous, in the epidermis at a certain area of the Malpighian network, the amount of pigment is always sharply increased; in verrucous N. in the papillary layer around blood vessels, there is a significant number of star-shaped "naevus" cells (Naevuszellen) containing pigment, sometimes isolated, sometimes collected in heaps and strands; in addition, usually more or less significant amounts of pigment grains are located freely. In verrucous and especially ichthyosiform N., in addition to increased pigment, thickening of the horny layer is noted; in N. pilosus—increase in the number of hairs; in N. sebaceus—hypertrophy and hyperplasia of the sebaceous glands.- Etiology. Dermatologists classify pigmented N. as congenital skin anomalies. Albrecht considers them hamartomas and explains them by excessive development of one tissue to the detriment of another (see Hamartoma). There are no scientific data confirming that psychological or physical factors acting on the mother during pregnancy would influence the development of pigmented N. Meirowsky considers pigmented N. to be phenotypic formations. Siemens, based on twin studies, concludes that pigmented N. are phenotypic formations, but in some cases there is a genotypic predisposition. Recently, it has been suggested that the factor causing the formation of pigmented N. is contained in the cells of an autosome. Adenomatous N. Darie includes in this group dermatoses that are still described as independent skin diseases: atheromas (loupes), hydrocystomas (n. syringo-adenomatosus), symmetrical and asymmetrical facial adenomas and hydroadenomas. Among these diseases, there are transitional forms, which are difficult to attribute to one or another of the mentioned dermatoses based on clinical, and sometimes histological, pictures. For example, in one case described as "adenoma of the sweat glands of the lower eyelids," histological examination revealed changes in the sweat glands as well as changes in the hair follicles, sebaceous glands and epidermis, i.e., those very changes that are characteristic of the diseases described under the general name "adenoma sebaceum" (Olesov).- The etiology of diseases in this group has not been clarified. There are individual data that allow classifying it in the group of hereditary diseases. For example, Siemens, Levit and others described families where atheroma was a dominant trait. There are cases where symmetrical facial adenoma was also a familial disease (figure 1). This assumption is confirmed by the fact that naevus molluscum-like (N. mollusciformis) often combines, on the one hand, with a group of dermatoses described under the name adenoma sebaceum, and on the other hand, with Recklinghausen's disease, a disease undoubtedly genotypic. The special interest of this group of dermatoses lies in the fact that a single factor, located in different parts and organs, gives completely different clinical and histological pictures. For example, in symmetrical adenomatous N. of the face, tumors are found not only on the facial skin but also in the kidneys, liver, myocardium and brain (Pelagatti).- The clinical picture corresponds to the location of the tumors. For example, with localization of nodules in the brain—tuberous sclerosis of the brain, with localization on the facial skin—so-called adenoma sebaceum, etc. Simultaneous involvement of the brain, facial skin, liver, etc. can occur in one person, but this involvement in various combinations is much more often found in different people in the same family (figure 2). The latter is especially important to know when studying the etiology of the disease, since the study of these dermatoses from the standpoint of heredity can be very difficult due to the fact that in addition to the different clinical picture, the disease may not be clinically detected (tumors in the liver, kidneys) or weakly detected (tuberous sclerosis of the brain). Vascular N. There are naevi consisting of neoplasms and dilatation of blood vessels and lymphatic vessels. The former are called angiomas (see), the latter—lymphangiomas (see). The former are divided into 1) flat vascular birthmarks (wine stains, p. vinosus), 2) nodular vascular N.—verrucous angiomas, they can reach significant sizes (p. vasculosus giganteus), 3) star-shaped angiomas.- Flat

In women, numerous naevi (fibromata, pendula, etc.), adenoma sebaceum and pendula colli pendula colli, adenoma sebaceum and tuberous sclerosis of the brain. Figure 2. Fig. 1. Adenoma sebaceum (Klauder's case). Figure 2. Adenoma sebaceum and tuberous sclerosis of the brain (Siemens' case). Vascular birthmarks (angio-ma simplex, naevus vascularis) clinically present as changes in skin color; they vary in shape, outline, and size from a pinhead to extensive surfaces. Their color ranges from bright pink to dark blue (N. flammeus); sometimes due to significant arterial development, they pulsate. They often appear on the face, hands, and particularly frequently in children on the forehead or on the nape at the border of the hairy part of the head; the latter type of birthmark is called N. vascularis infantilis occipitis and is particularly prone to spontaneously disappear with age (after 1 year they are almost nonexistent).-Nodular vascular naevi are colored bright red or dark blue, rise above the surface of the skin, and are usually sharply demarcated, less often have diffuse edges. Sometimes they pulsate. Located on various parts of the body, they can severely deform the lips, nose, ears, tongue, etc., in other cases not only the skin but also the mucous membranes of the mouth and nose are affected. These naevi in other cases affect large areas of skin and severely disfigure the patient, sometimes interfering with their movements, and in other cases bleed profusely. Three types of these naevi are distinguished: the first type has a tendency to regress either through fatty degeneration or sclerosis of the tissue, usually starting from the central part of the naevus; in the second type, the elements of the lesion remain unchanged for a very long time, and finally the third type of naevus is characterized by progressive peripheral growth (naevus serpiginosum; R. Crocker).-Star-shaped angiomas (N. stellatus or arachnoideus) usually appear during or after puberty. They consist of a central red point raised above the skin, from which dilated vessels branch out radially like the legs of a spider.-Lymphangioma represents a naevus consisting of hyperplastic and hypertrophied lymphatic vessels and spaces; it is rare; clinically it is characterized by the appearance on the skin of tumors ranging from the size of a millet seed to a pea and larger; their color is reddish-brown or the color of normal skin; it is usually congenital but can also develop at a later age; once it appears, it remains for life. Under the term "connective tissue naevi" (naevi connectivi) are described lesions located in groups or linearly, most often on the chest, closely crowded "like a mosaic", but always isolated nodules, flat or slightly spherical, round or polygonal, from a pinhead to a small shot in size, colored from white to yellowish-pink, more noticeable under side lighting or when stretching the skin and sometimes having an expanded opening of a hair follicle in the center, dense to the touch. Histologically: hypertrophy and homogenization of collagen in the middle and deep layers of the corium, sometimes with atrophy and destruction of elastin, sometimes hypertrophy of smooth muscle fibers and sebaceous glands.-As N. comedonicus, or acneiformis, are described lesions that exist for years, arranged linearly in several rows, large, dry and dense comedo-like formations that block the expanded openings of hair follicles and gradually cause scar atrophy of the affected area of skin, which is sometimes aided by accidental pyogenic infection with purulent folliculitis and perifolliculitis. Histologically-usual picture of pronounced ostial follicular keratosis, sometimes with a picture of chronic perifolliculitis; sometimes hypertrophy of sebaceous glands, presence of "fountain cells" and etc. Naevus anaemicus-see Leukopathies. Treatment of all types of naevi is generally difficult, it is necessary to individualize each case when choosing treatment, based on the conditions of its development. The following treatment methods are used: 1) chemical cauterization (they leave deep scars), 2) surgical method (excision of the entire tumor or scarification), 3) electrolysis, 4) radiotherapy, 5) treatment with radium and radon (especially indicated for nodular vascular naevi), 6) treatment with snow of coal acid; this method is recommended for all flat naevi, and in the absence of radium and X-rays also for vascular warty forms. In recent years, this method has received particularly wide application due to the invention in France and Germany of tips that allow the use of snow coal acid in the form of very thin cauterizations. The latter method indeed in many cases gives excellent results, leaving delicate and superficial scars. For N. arachnoideus, electrolysis or galvanocautery is recommended, and it is sufficient to destroy the central point with a needle for the entire naevus to regress. In newborn infants, the first two types of nodular vascular angiomas may still be left untreated, but the third type should be treated as soon as possible, with radiotherapy giving good results.