Seborrheic keratosis

Introduction to seborrheic keratosis Seborrheic keratosis, also known as seborrheickeratosis, is the most common benign epidermal proliferative tumor in the elderly. Almost all elderly people suffer from this type of damage more or less. The damage caused by the disease occurs on the face, especially the ankle. The disease is a benign tumor, but a few will have malignant transformation. basic knowledge The proportion of illness: 0.04% Susceptible people: the elderly Mode of infection: non-infectious Complications: pruritus

Causes of seborrheic keratosis

Causes:

The exact cause to date is still unknown. Multiple, but not confirmed. The relevant factors of several doctrines are listed below:

Genetic (30%):

Seborrheic keratosis, sometimes with a family history, indicates that the disease has a genetic predisposition. Because the disease has a wart appearance, suggesting that its cause may be related to human papilloma, but after repeated studies, no evidence of the virus and the disease has been found. Epidermal growth factor is involved in the development of this disease. The appearance of rash in multiple seborrheic keratosis, accompanied by various visceral malignant tumors, acanthosis nigricans and other epidermal hyperplasia suggest that tumor-derived circulating growth factors may be involved in the pathogenesis of these lesions. But so far there is no definitive evidence.

Melanocyte hyperplasia (30%):

Melanocyte proliferation is common in seborrheic keratosis. It also suggests that melanocytes and melanocyte-derived growth factors may play a role in the development of seborrheic keratosis.

Pathogenesis:

The disease can be divided into 6 types by pathology, namely keratinized, acanthosis, nested, adenoid, stimulating and melanoma acanthoma. But often mixed. All types have hyperkeratosis, acanthosis and papillary hyperplasia. It is characterized in that the base of the tumor lesion is located on the same level, and both ends are connected to the normal epidermis. Two types of cells can be seen in the hyperplastic epidermis, one is a spine cell or a squamous cell, which is the same as the squamous cell seen in the normal epidermis, and the other is a basal-like cell, similar to the epidermal basal cell, but the normal basal cell is Small, the nucleus is relatively large, and this basal-like cell is also a characteristic of this disease. The changes of various types were also different. The hyperkeratosis and papillary hyperplasia were more prominent in the keratotic type, while the acanthosis was not obvious. The epidermis was mostly composed of squamous cells.

Seborrheic keratosis prevention

Most of the seborrheic keratosis occurs in the elderly. Although it is also seen in young people, it usually occurs after 30 to 40 years of age. In the past, this disease was considered to be a delayed epithelial sputum, benign epithelial tumor, senile skin changes or infectious lesions, but the exact cause to date is unknown. Therefore, there are no clear preventive measures.

Life restraint pays attention to rest, work and rest, life is orderly, and maintaining an optimistic, positive and upward attitude towards life is of great help in preventing diseases. Do the regularity of tea and rice, live daily, not overworked, open-minded, and develop good habits.

Seborrheic keratosis complications Complications pruritus

It can cause symptoms, ulceration, hemorrhage, scarring and irregular hyperplasia due to repeated frictional stimulation. Because the disease may be accompanied by itching and the integrity of the skin is destroyed, it may cause skin bacterial infection or fungal infection due to scratching, usually secondary to low constitution, or long-term use of immunosuppressants and fungal infections such as onychomycosis. Such as concurrent bacterial infections may have fever, skin swelling, ulceration and purulent secretion and other performance. Severe cases can lead to sepsis, which should be brought to the attention of clinicians.

Seborrheic keratosis symptoms common symptoms horn plug chest itching scaly papules

The disease is common in patients over 30 years old. The skin lesions begin with one or more flat-brown or brown spots with a clear flattening, round, oval or irregular shape. The surface is velvety to mildly sinuous. Large, increased number, darker color, brownish black or even black scorpion papules or plaques, no more than 3cm in diameter, with greasy scales on the surface, so it is called seborrheic keratosis, many damage to the surface visible angle plug, Skin lesions can occur in any part other than mucosal palmar. However, the most common in the face and the middle of the trunk, the skin lesions usually do not self-resolved, benign, and very few malignant changes.

1. Damage occurs on the face, especially the ankle, followed by the back of the hand, the trunk and the limbs.

2. The beginning is light brown or dark brown or black, the diameter is generally not more than 3cm, the boundary is clear, the surface is smooth. Afterwards, the skin lesions gradually enlarged and the pigmentation was dark brown or black. The surface is rough and sturdy, forming a layer of oily thick enamel soft and brittle. After peeling off the skin, it has a rough and moist base. The surface is papilloma-like. The hair follicle horn is one of the important features, usually without symptoms. Occasionally itching.

3. Multiple seborrheic keratoderma lesions may occur in the short term, possibly with visceral malignant tumors.

The course of the disease is slow and the damage can be enlarged or merged into large pieces.

Examination of seborrheic keratosis

Histopathology: The pathology of this disease presents a variety of different manifestations, usually divided into 6 types, namely keratinized type, acanthosis type, colony type, adenoid type, stimulating type and black echinoderma type. In the same damage, more than one is common. The above type of type.

All of the above types have hyperkeratosis, acanthosis and papillary hyperplasia. In most cases, the acanthosis is due to the tumor stretching upwards. Therefore, the lower end of the tumor is flat and is at the same level as the normal skin at both ends. Pathological features of the disease, the proliferating tumor tissue consists of squamous cells and basal-like cells, the former is the same as the squamous cells seen in the normal epidermis, while the latter is smaller than the normal basal cells, and the nucleus is relatively large. The above six types are described as follows:

1. Spinous layer hypertrophy: the most common type of this disease, hyperkeratosis and papilloma are often light, but the epidermis is significantly thickened. In some cases, the thickened epidermis only surrounds the narrow nipple, and other cases It can be seen that the thickened, interwoven epidermal cell cord surrounds the connective tissue island to form a net-like appearance. It can be seen that many keratinous depressions appear as many pseudo-horn cysts on the transverse plane, in addition to true cysts that are suddenly but completely keratinized. In the significantly thickened epidermis, the number of basal cells exceeds that of the squamous epidermis, and this type of melanin is more than normal.

2. Hyperkeratosis type: also called finger or zigzag type, hyperkeratosis and papilloma-like proliferation, but the acanthosis is not obvious, many dermal papilla with surface covering the epidermis, extending upwards like a church On the roof, the epidermis is mostly composed of scaly epidermis, but small clusters of basal-like cells are everywhere, and generally there is no large amount of melanin.

3. Adenoid: The epidermis has many fine epidermal cell bundles extending from the epidermis to the dermis and branching and interweaving. Many bundles consist only of bilayer basal-like cells, pure reticular lesions without keratinous cysts and pseudokeratinous cysts, but adenoids Types are also often associated with acanthosis, the latter common keratinous cysts and pseudokeratinous cysts, adenoid basal-like cells often have obvious pigmentation.

4. Colony type: There is a very significant cell nest in the epidermis. In some cases, the nucleus is small and deeply stained. Only in a few places, the intercellular bridge is seen, but similar to the lesion of basal cell epithelial tumor, some cases Cell nests are made up of fairly large cells with distinct intercellular bridges.

5. Stimulating type: This type is characterized by the appearance of many scaly vortices or scaly beads composed of many eosinophilic flat squamous cells arranged in onion, so that they are like keratinized beads with low differentiation, but these scaly vortices are small. The number is large, and it is bounded and easily differentiated from the horn of squamous cell carcinoma. In addition, stimulating seborrheic keratosis can grow downwards, exceeding the horizontal boundary normally seen by non-stimulation.

6. Acanthoma cell type: a rather rare histological type of seborrheic keratosis. There are many large melanocytes filled with melanin in the lesion. Silver staining these cells has large dendrites and contains considerable The amount of melanin, while keratinocytes are almost free of any melanin, this type is different from the usual pigmented seborrheic keratosis, which has only a few melanocytes, and melanin is almost completely located in keratinocytes.

Diagnosis and differentiation of seborrheic keratosis

diagnosis

The diagnosis of the disease combined with clinical and pathological is not difficult, especially the pathology is characteristic.

However, more skin lesions of seborrheic keratosis occurred suddenly after middle age. When accompanied by itching, consideration should be given to the possibility of the Leser-Trelar sign, a sign of a visceral malignancy, especially adenocarcinoma or lymphoma, Sezary syndrome or acute leukemia. The rash usually occurs at the same time as the tumor or shortly after it occurs.

Differential diagnosis

1. Melanoma: It is easy to be confused with isolated black seborrheic keratosis. The surface of melanoma is smooth and the appearance is mildly infiltrated rather than sickle. Histopathology can confirm the diagnosis.

2. Actinic keratosis: usually erythema, rough surface, mild scales, no greasy scales, unclear skin lesions, most often in the exposed area, especially face and back, more common in skin white Clear patients, histopathology can be identified.

3. cell : smooth surface is not sputum-like, no seborrheic scaly, histopathology can be identified.

4. Senile freckle-like sputum: The skin lesions are located in the sun, so it is also called solar freckle-like sputum, which is a light brown or dark brown plaque of different sizes, not higher than the skin surface, and early seborrheic keratosis The damage is similar, but the seborrheic keratosis is clinically keratinized slightly, slightly higher than the skin, may have seborrheic scales, and histopathology is different and can be distinguished.

5. Pigmented basal cell carcinoma: irregular shape, with a pearl-like curled edge, the epidermis is thin and shiny, may have telangiectasia, central depression or ulceration, and histopathology is characteristic.

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