Claws and nail beds appear as longitudinal pigmented bands

Introduction Malignant melanoma (smear) is a malignant tumor derived from normal melanocytes or primitive sputum cells. Although it is rarer than skin cancer, it has a high degree of malignancy, rapid progression, sinister disease and poor prognosis.

Cause

1. cell malignant transformation: In the past, it was thought that skin MM originated from the malignant transformation of sputum cells, especially junctions. In recent years, it has been considered that skin MM is related to sputum cell sputum, but it is not entirely true. MM cells are derived from intradermal dermal sputum cells rather than so-called border type sputum cells. According to statistical health search, MM occurring in the trunk or limbs (except palm and sputum) is 35% to 50%, and the original intradermal type dermis It is related to sputum cells. Undoubtedly, primary skin MM can originate from the original melanocytes in the epidermis and some of the pre-existing congenital (usually large, such as congenital giant python) and acquired intradermal sputum cell sputum.

However, about 1/3 of MM patients have no history of sputum cell history. For example, Clark (1969) has histological observation of two groups (209 cases and 60 cases each), only 20 cases (9.6%) and 5 cases (8.3 cases respectively). %) is related to sputum cell sputum. In addition, MM occurs in exposed areas such as face and scalp. This is not the predilection of the cell sputum, the sputum MM mostly has nothing to do with sputum cell sputum. Therefore, some people think that MM is not completely related to sputum cell sputum. However, any sputum including pigmented skin lesions, when sudden growth accelerates, pigmentation darkens or becomes shallow, irregular pigmented halos appear around, or pigmentation halo, itching, stinging surface scaling, secretion, scarring, Destructive bleeding, hair loss, satellite nodules in the vicinity, or regional lymph node enlargement with unexplained causes should be considered as an indication of the beginning of malignant transformation requires careful attention.

2. Ultraviolet radiation: Repeated irradiation of ultraviolet light at a wavelength of 290 to 320 nm can not only cause an increase in the number of melanocytes, but also cause a qualitative change. The incidence of MM is related to the exposure of sunlight, especially ultraviolet light. The incidence of MM in the South of Norway is almost twice that of the North. According to Israeli statistics, the incidence of agricultural workers MM (15.4/100,000 per year) is higher than in cities (1.7/10 million per year); coastal areas (3.5/100,000 per year) are higher than mountains (2.0/10 million per year). Some people think that malignant freckle-like MM is related to direct sunlight. Non-exposed parts of nodular MM may be due to sunlight. The exposed skin releases a substance into the blood (daylight cycle factor) and acts on non-exposure sites. Caused by melanocytes of the skin.

3. Race: Caucasians have a higher incidence of MM than people of color. The incidence of Caucasians in the United States can be as high as 42/100,000 per year, while that of blacks is only 0.8/100,000 per year.

4. Genetics: Patients with family members are susceptible to this disease. Anderson (1971) reported 74 of the 22 families. There have also been reports of healthy searches for identical twin patients. The age of onset of familial patients is about 10 years earlier than usual. Some hereditary skin diseases such as xeroderma pigmentosum can occur in 50% of patients with this disease.

5. Trauma and irritation: This disease often occurs in the scalp, palms, soles and other areas often suffering from friction. Many young female patients often have a history of pointing many years ago. It is estimated that 10% to 60% of patients have a history of trauma, including crush, stab wound, blunt injury, armor, burn or X-ray.

6. Viral infection: Virus-like particles were found in MM cells of voles and humans.

7. Immune response: This disease is more common in the elderly, and the incidence increases with age. In addition, there may be a self-resolving phenomenon, indicating that the occurrence of this disease has a certain relationship with the patient's immune response.

an examination

Related inspection

Tumor associated antigen tumor gene P53 antibody (P53-AB)

1. History and symptoms:

Detailed medical history and physical examination are important for diagnosis. Any pigmented skin lesions on the body surface, if sudden growth accelerates, there are pigmentation halos or pigment loss around, surface scaly, exudation, ulceration, hemorrhage, local itching of satellite nodules near the hair removal, etc. The occurrence of tumors.

2. Laboratory inspection:

(1) Urine examination: Usually the laboratory examination does not help the diagnosis. However, when the melanoma has undergone extensive metastasis, a large amount of melanogen and its metabolites may appear in the urine and it is black urine.

(2) Histopathological examination: should be made to determine the nature of the melanoma, the type of tumor, the depth of invasion, the maximum vertical thickness, the cell division, the presence of ulcers on the surface, the invasion of basal vessels and lymphatic vessels, and the presence or absence of cellular inflammatory reactions. Diagnostic description. For patients who have been diagnosed with melanoma, detailed examination of regional lymph node metastasis and distant metastasis should be performed.

These are important for developing treatment options and estimating prognosis. Studies have shown that health search, clinically found by palpation in patients with regional lymph node metastasis compared with selective lymph node dissection, microscopic lymph node micrometastasis (micrometastasis) or subclinial metastasis (subclinialmetastasis) are reduced by 20%. ~50%. Therefore, early determination of lymph node micrometastasis is important for improving 5-year survival.

Differential diagnosis

Malignant melanoma should be distinguished from pigmented nevi, pigmentary basal cell carcinoma, pigmented seborrheic keratosis, cutaneous fibroids or sclerosing hemangioma. A subcutaneous melanoma must be distinguished from an old subcutaneous hematoma.

1. History and symptoms:

Detailed medical history and physical examination are important for diagnosis. Any pigmented skin lesions on the body surface, if sudden growth accelerates, there are pigmentation halos or pigment loss around, surface scaling, exudation, ulceration, hemorrhage, local itching of satellite nodules near hair removal, etc. The occurrence of tumors.

2. Laboratory inspection:

(1) Urine examination: Usually the laboratory examination does not help the diagnosis. However, when the melanoma has undergone extensive metastasis, a large amount of melanogen and its metabolites may appear in the urine and it is black urine.

(2) Histopathological examination: should be made to determine the nature of the melanoma, the type of tumor, the depth of invasion, the maximum vertical thickness, the cell division, the presence of ulcers on the surface, the invasion of basal vessels and lymphatic vessels, and the presence or absence of cellular inflammatory reactions. Diagnostic description. For patients who have been diagnosed with melanoma, detailed examination of regional lymph node metastasis and distant metastasis should be performed. These are important for developing treatment options and estimating prognosis. Studies have shown that health search, clinically found by palpation in patients with regional lymph node metastasis compared with selective lymph node dissection, microscopic lymph node micrometastasis (micrometastasis) or subclinial metastasis (subclinialmetastasis) are reduced by 20%. ~50%. Therefore, early determination of lymph node micrometastasis is important for improving 5-year survival.

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