Pigmented nevus

Introduction to pigment enamel Pigment nevus, also known as nevocytic nevus, is a pigmented lesion composed of sputum cells, usually called sputum, melanoctic nevus or melanocyte sputum. It is the most common benign tumor of the skin. Everyone has skin that can occur in any part of the body, but it is most common in the face and neck. A few can occur in the mucous membranes, such as the lips, labia, and sputum. Can be congenitally or acquired, most of them grow slowly, or remain unchanged for many years, less natural regression, individual types of sputum, there is junctional vitality, malignant transformation can occur, usually there is a process of development and degradation. In the early childhood, it is a flat junction, and it grows into a composite or intradermal fistula with puberty. basic knowledge The proportion of sickness: 0.01% Susceptible people: no special people Mode of infection: non-infectious Complications: skin cancer

Pigmentation

cell composition (30%):

Pigment sputum is composed of sputum cells containing pigments. There are different opinions about the source of sputum cells, or melanocytes derived from the epidermis, or precursor cells derived from neural crest during embryonic period. The cells have a dual source, that is, the sputum cells located in the upper part of the epidermis and the dermis are derived from epidermal melanocytes, while the sputum cells located in the lower part of the dermis are derived from the nerve Schwann cells. During the migration of the above cells to the epidermis, due to some abnormal factors, And cause abnormal distribution of melanocytes.

Diversity (30%):

The shape of sputum cells is diverse, and it looks like epidermal cells in the epidermis and dermis; in the middle and lower part of the dermis, it is like tissue cells, fibroblasts, lymphocytes or Schwann cells. In the skin, sputum cells are nested, lacking dendrites. The tyrosinase activity is low; there is no desmosome or intercellular junction on the ultrastructure, and there are mitochondria, Golgi complex, melanosome and the like similar to melanocytes.

Pathological changes (30%):

According to the location of sputum cells in the pathological section of the skin, there are three basic types: 1 junction : cells are concentrated at the junction of epidermis and dermis, 2 intradermal : all sputum cells are concentrated in the dermis, 3 mixed: cells can be seen at both the epidermal-dermal junction and also in the dermis. It has the dual characteristics of border ridge and intradermal ridge.

In addition to pathological classification, there are other sputum cell sputum named after clinical features, such as syncope, Spitz, giant clam, dysplasia and so on.

Pigmentation prevention

There are no special preventive measures for this disease. Early detection and early treatment are the key to prevention.

Pigmented nevus complications Complications skin cancer

Pigment nevus, also known as nevocytic nevus, is a pigmented lesion composed of sputum cells, usually called , melanoctic nevus or melanocyte sputum. It is the most common benign tumor of the skin. Pigment nevus is available to almost everyone, and can occur in any part of the body, but is most common in the face and neck. A small number can occur in mucous membranes, such as lips, labia, and sputum. It can be innate or acquired. Most grow slowly, or remain unchanged for many years, and less naturally fade. Individual types of cockroaches have the vitality of junctions and can be malignant.

Symptoms of pigmented nevus common symptoms acne rash skin hemosiderin pigmented spotted rash cell nodules pigmentation eczema blush skin gradually dark black

Pigmentation occurs in children or adolescence, and can be characterized by rash, papules, papilloma, sputum, nodules or pedicle damage. It can occur in any part, and the number increases significantly with certain malignant melanoma. Risk, pigmented nevus size from a few millimeters to a few centimeters, or even large area, often symmetrical, clear boundaries, smooth edges, uniform color, depending on the pigment content of the cells, the color can be yellow, brown or black, but also It can be blue, purple or near skin color. Some lesions can penetrate short and thick black hair. The pigmentation of congenital pigmented nevus is early and the skin lesion is large, and the pigmentation of acquired pigmented nevus requires certain stimulating factors. Under the influence of sun exposure, hormones, vesicular diseases, immunosuppression or chemotherapy, sputum rapidly increases.

Clinical manifestation

According to the different parts of the sputum cells, their clinical manifestations are also different. Common types are:

(1) Junctional nevus is more common in children and young adults. It is rare in adulthood and can occur in any part of the mucous membrane of the skin. However, the pigmented nevus in the palms, ankles, red lips and genitals is almost a junction, which can be regarded as A well-developed area, characterized by a flat or slightly raised round or oval pigmented spot or papule, with a smooth surface, no hair, light brown to black, and a diameter of 1 to 8 mm. As shown in Figure 1, the cells of the junction have Increasing the active characteristics, called junctional vitality, has the potential to transform malignant melanoma.

(2) intradermal nevus (intertradermal nevus) is more common in the elderly, showing flat or higher than the leather surface, or scorpion or pedicle, usually less than 1cm in diameter, brown or black, the surface is smooth or rough Sometimes one or a few hairs in the center are visible (Figure 2).

(3) Compound nevus is more common in young and middle-aged people, showing mildly raised skin, brown to black hemispherical papules or maculopapular rash, clear boundary, often hair growth as shown in Figure 3. There is a vitality in the junction, so there is also the possibility of malignant transformation.

(4) halo nevus (halo nevus) is named after the pigmentation periorbital around the pigmentation, also known as acquired telecentric leukoplakia, the center of the pigmented nevus is about 0.5cm in diameter, and the size of the pigmentation halo is several millimeters. As shown in Figure 4, the torso, face and neck are more common, can be single or multiple, common in adolescents, no symptoms, pathological often mixed sputum, but also intradermal sputum.

(5) Spitz (Spitz nevus) Also known as benign juvenile melanoma, fusiform and epithelioid cell sputum, pseudo-melanoma, is a type of sputum, mostly mixed sputum, but also intradermal sputum or junction , is pink, fuchsia, tan or black papules or small nodules, the boundary is clear, usually the surface is smooth and hairless, the diameter is generally <1cm, which occurs in the face and lower limbs, and can also be found in other parts. More common, histologically similar to malignant melanoma, but in biological behavior is usually benign, it is known as benign juvenile melanoma or pseudo-melanoma.

(6) congenital pigmented nevus (congenital pigmented nevus) exists at birth, characterized by a large lesion area. Some authors advocate that the lesion area >900cm2 is the diagnostic criteria for giant scorpion. Some authors believe that >2% body surface area is Juju, there are still authors who believe that it is not possible to define the size of the giant scorpion, some of which occur in the neck and face of the eyelids or auricles, or in the special parts of the hands, genitals, anus, etc., although the area is not enough, but the area is not enough If surgical resection is performed, the wound treatment is more complicated, and it should also be called python.

Giant pythons are usually brown to dark black, with different shades, rough surface, uneven height, and can have ridges, and thick and long hair grows as shown in Figure 5, so there is a giant python, giant distributed on the side of the body, known as unilateral pigmented nevus, occurs in the scalp and neck, may be associated with pia mater hyperplasia, epilepsy and mental disorders, and even primary pia mater Tumor, located in the spine, may be accompanied by spina bifida, meningocele and other deformities. In histopathology, Eucalyptus is mixed with sputum or intradermal fistula.

(7) dysplastic nevus (dysplastic nevus), also known as BK , clinical manifestations of light brown, light red or brownish black, central high, border is not clear, single or multiple pigmentation spots or papules, diameter 5 ~ 15mm, It occurs in the trunk, followed by the limbs, and again on the face. It is more common among young and middle-aged people. The vast majority of histology is mixed, and a few are expressed as borders.

2. Rare types of clinical manifestations

(1) Eczema-like changes: Occasionally, redness-like eczema dermatitis appears around the pigmented nevus, which has a itchiness and subsides after a few months.

(2) Lace-like sputum: It is characterized by the center of the pigmented enamel, the surrounding pigmentation halo, and the sputum cells in the pigmented halo are composed of borderline sputum cell nests, and have obvious cell atypicality.

The clinical diagnosis of sputum cell sputum is generally not difficult according to its performance characteristics, but the accurate pathological nature judgment is not reliable according to the naked eye, and the diagnosis must rely on pathological examination.

Pigmentation examination

Regular physical inspection.

Pathological diagnosis.

Histopathological examination showed that there were nested, non-dendritic sputum cells in the skin.

Diagnosis and identification of pigmented nevus

diagnosis

Diagnosis can be performed based on clinical manifestations and examinations.

Differential diagnosis

1, giant clam

Greeley believes that the body of the torso and limbs, whose area is more than 900cm2, is a giant clam. The author believes that the standard of pythons should vary according to age, location, etc., such as pigmented enamel in specific parts such as face, although the area is less than the above standard, but After surgical resection, the wound can not be directly sutured, it can also be regarded as giant python, and infants can not use this standard constant. The python is already present at birth, and many common parts are invaded. The surface is often uneven, rough and fat, and common. With hair, the pathological nature of the giant disease belongs to mixed sputum or intradermal sputum, so there is also the possibility of transformation into malignant melanoma.

2, blue dragonfly

It is characterized by cyanine, dark blue, or isolated lesions of papular-like or small knot-like lesions. It is divided into two types: general type and cell type. The general type is small, the diameter is generally less than 1.5cm, and the surface is smooth and tough. The cell surface is rough and the area is often large. It is more common in women. The pathological examination is generally blue-type. In the middle and lower layers of the dermis, long flat melanocytes are visible, while the cell type has a larger round or shuttle. The shape cell island has a different shape of the nucleus, the lesion can be deep and the subcutaneous fat layer, and the cell type blue sputum can be malignant, but it is rare.

3. Ota

In 1938, Japan's Ota first reported a gray-blue plaque that affects the sclera and the trigeminal nerve distribution in the same side. It is also called the brown cyan sputum on the upper eyelid. This sputum is often plaque on one side of the face, about 2 /3 patients with the same side of the sclera blue staining, about 1/2 of the patients already exist at birth, the remaining patients appear after 10 years old, the pathology see melanocytes scattered between the dermal collagen fibers, some deep tissues such as the orbital periosteum may also have Melanocyte infiltration.

4,

Light brown, brown or stained black, papular-like, papillary or sputum-like lesions, excessive keratinization of the surface, often confined to one side of the body, more than already present at birth or during childhood, histological examination, There is a significant hyperkeratosis in the epidermis. The spinous cell layer is irregular and hypertrophic with papillary changes. The melanin of the basal cell layer tends to increase, and no innocent cells or inflammatory cells infiltrate.

5, freckles

In order to diffuse the scattered distribution of countless small light brown spots, the surface is smooth, does not highlight the leather surface, occurs in the exposed part of the body, the most prominent face, occasionally neck, shoulder, back of the hand, tissue biopsy, The number of melanocytes does not increase, but a large number of pigment particles are abnormally formed, and freckles have no tendency to become malignant.

6, senile dark spots

Occurred in the exposed parts of the middle-aged and the elderly, such as the cheeks, neck, back of the hand and forearms, scattered in tan, small rounded in size, elliptical or irregularly smooth or slightly higher The plaque on the skin surface, histological examination, shows that normal melanocytes increase, and no malignant changes occur.

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