Dermatofibroma

Introduction to cutaneous fibroma Dermatofibroma, also known as sclerofibroma, is a benign tumor in the dermis caused by fibroblast or tissue cell focal hyperplasia. The disease can occur at any age, but is more common in young and middle-aged women than in men. basic knowledge The proportion of sickness: 0.2% Susceptible population: This disease can occur at any age, but it is more common in young and middle-aged women than in men. Mode of infection: non-infectious Complications: leiomyomas of the skin

Cause of cutaneous fibroma

(1) Causes of the disease

The cause is unknown. Some cases may be related to local minor injuries, such as insect bites or blunt injuries. Some people think that it is also related to viral infection. Ackerman believes that the disease is reactive rather than neoplastic, Yang Meilin et al. (1992). Observed by electron microscopy, a large number of immature mast cells in the skin fibroids are in close contact with fibroblasts. The fibroblasts can be seen and developed into a cystic rough endoplasmic reticulum, indicating that the function is active and that mast cells are increased. May be the cause of fiber proliferation.

(two) pathogenesis

The nodule is located in the dermis, without capsule, the boundary is unclear, and it is obviously interlaced with the surrounding normal tissue; the lower boundary is clear, and the upper boundary and the epidermis are often sandwiched by a "border band" composed of immature collagen fibers, but the tumor tissue Sometimes it can be attached to the epidermis, and the cut surface is grayish, yellowish brown or dark brown.

Under light microscopy, fibroblasts, histiocytes, endothelial cells and mature or naive collagen fibrotic tissue can be seen in the lesions. How many indefinite dilated capillaries can be seen in the tumor tissue, and the endothelial cells are obvious; some tumor cells are stained with cytoplasm. There are vacuoles, which become typical foam cells (fat deposits); there are hemosiderin deposits inside and outside the tumor cells, and the epidermis above the center of the lesion has obvious hyperplasia, acanthosis hypertrophy, skin protrusion prolonged, and occasional nuclear mitosis But not typical.

According to the proportion of cellular components and collagen fibers, there are two types of lesions:

1. Fibrous type: Most of the disease, almost entirely composed of fibroblasts and collagen fibers. The fibroblasts have a rhomboidal shape with little cytoplasm, and most of the collagen fibers are naive, light blue, and scattered. A bundle that is not dense, arranged in an irregular braid or in a spiral.

2. Cell type: cell type (tissue cell tumor), the main component is tissue cells (phagocytic cells), collagen fibers are few, also naive, tissue nuclei are round or elliptical, cytoplasm is rich, irregularly arranged.

Dermal fibroma prevention

prevention:

Because the cause of cutaneous fibroids is not yet clear, the method of prevention is nothing more than:

1 to minimize infection and avoid exposure to radiation and other harmful substances, especially drugs that have an inhibitory effect on immune function;

2 Appropriate exercise, enhance physical fitness and improve your disease resistance.

It is mainly aimed at preventing various factors that may cause skin fibroids. It is currently believed that the loss of normal immune surveillance function, the tumorigenic effect of immunosuppressants, the activity of latent viruses and the long-term application of certain physical (such as radiation), chemical (such as anti-epileptic drugs, adrenocortical hormone) substances, Lead to the proliferation of lymphatic network, and eventually skin fibroids. Therefore, pay attention to personal and environmental hygiene, avoid drug abuse, and pay attention to personal protection when working in a harmful environment.

Dermal fibroma complications Complications, leiomyomas of the skin

Skin fibroids can cause ulceration after trauma.

Symptoms of cutaneous fibroids Common symptoms Tumor hard nodules papules round or oval dome...

1. Good hair

More common in the extremities of the extremities, occur in the lower limbs, above the elbow or on both sides of the trunk and shoulders and back, other parts can also occur.

2. Clinical symptoms

(1) Skin lesions: clinically diagnostic value, intradermal papules or nodules, bulging, hard, base can be pushed, but connected to the epidermis, the surface of the skin is smooth or rough, the color is different, can be normal skin tone, Can also be yellowish brown, dark brown or light red, more common in middle-aged adults, rare in children, usually round or oval rash or nodules, about 1cm in diameter, usually no more than 2cm, even 2cm or more, Skin lesions often persist and can resolve on their own after several years.

(2) usually no symptoms, occasionally or mild pain, some patients can develop multiple cutaneous fibroids, the latter with lupus erythematosus and HIV infection with prednisone or immunosuppressive agents .

(3) Generally, it is a single hair, or 2 to 5, even or multiple, the surface of the nodule is smooth or rough, and is often single, even or multiple.

3. Clinical signs

It has a solid nature and is hard to touch. It is attached to the epidermis and does not adhere to the deep tissue. The lower part can move freely. When the lateral pressure is pressed, the center of the nodule is tiny dimples. It is characteristic. Fitzpatri proposed "dimple sign". One to indicate its characteristic, "dimple" sign positive (use the thumb and forefinger to pinch the tumor from both sides, showing that the skin above it is slightly subsided).

Examination of cutaneous fibroids

Histopathology: histopathological examination showed gray, white or brownish brown; the lower boundary was clear. Fibroblasts, histiocytes, endothelial cells and mature or naive collagen fibrotic tissue; the central epidermis of the lesion has obvious hyperplasia, acanthosis hypertrophy, prolonged skin process, and can be divided into two types: fibrotic lesions and cell type damage. The composition of the immature collagen fibers, light blue, irregularly arranged into a woven interlaced strip, spiral or wheel-shaped, with fibroblasts with narrow nuclei between the fibers, the latter consisting of a large number of fibroblasts and a small amount of collagen fibers Composition, many cells have large, round or oval nucleus, rich in chromatin, rich in cytoplasm, cells may contain lipids in the form of foam or containing hemosiderin, sometimes cells can be atypical.

Most of the cells were positive for -factor, MAC387-negative, S-100 protein-negative and CD34-negative. The lesion had no obvious boundary with the surrounding tissue. It was separated from the normal epithelium with a narrow normal collagen fiber band, and the epidermis was obviously proliferated. The rule is prolonged, with increased pigmentation in the basal layer, and has diagnostic value.

Diagnosis and diagnosis of cutaneous fibroma

diagnosis

According to clinical manifestations and histopathology, immunohistochemistry can be diagnosed.

1. History: Local history of minor trauma or viral infection.

2. Clinical features: intradermal papules or nodules, yellow-brown or reddish, etc., and no adhesion to deep tissues, "dimple" sign positive.

3. Histopathological examination: consistent with pathological changes of cutaneous fibroma.

Differential diagnosis

Clinically, it should be differentiated from granulosa cell tumor, disseminated soybean-like skin fibrosis, clear cell acanthoma, melanoma.

Protuberance cutaneous fibrosarcoma

There are many cellular components; the nucleus is large and has a slight abnormal shape, and the schizophrenia is more than 2 to 3 cm in diameter, suggesting that malignant fibrous histiocytoma, or hyperplastic cutaneous sarcoma, should be removed for biopsy.

2. Nodular pruritus

Occurs in the extremities of the extremities, multiple hairs and the same size, will not increase to a large extent, itching is obvious without tingling, often associated with insect bites, histopathology is epidermal squamous or papillary hyperplasia, no proliferative collagen fibers in the dermis And tissue cells.

3. Skin leiomyomas

It is similar to cutaneous fibroids, but it has pain. Histopathological examination shows that the tumor is composed of smooth fiber bundles criss-crossed. The nucleus is centered, rod-shaped, blunt at both ends, and collagen fibers are often found between muscle fibers. The two fibers are indistinguishable, but stained with Verhoeff-van Gieson, the collagen fibers are red and the muscles are yellow; if stained with Masson's three colors, the collagen is green and the muscles are dark red.

4. The disease also needs to be differentiated from malignant melanoma, nodular xanthoma, and keloid.

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