Skin malignant melanoma

Introduction to skin malignant melanoma 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. basic knowledge The proportion of illness: 0.002% Susceptible people: this disease is more common in the elderly Mode of infection: non-infectious Complications: acute lymphadenitis

Cause of skin malignant melanoma

(1) Causes of the disease

The etiology of melanoma has not yet been fully elucidated, and some research data suggest that its occurrence is related to the following factors:

1. cell aversion

In the past, skin MM was thought to be derived from the malignant transformation of sputum cells, especially border sputum. In recent years, skin MM is thought to be related to sputum cell sputum, but not completely. MM cells are derived from intradermal dermal sputum cells rather than so-called junctions. According to statistics, the MM occurring in the trunk or limbs (except the palm and sputum) is 35% to 50%, which is related to the original intradermal dermal sac cells. Undoubtedly, the primary skin MM can originate from the epidermis. Some melanocytes and some pre-existing congenital (usually large, such as congenital giant python) and acquired intradermal sputum cell sputum, but about 1/3 MM patients have no history of sputum cell, such as Clark (1969) had histological observation of two groups of patients (209 and 60, respectively), only 20 (9.6%) and 5 (8.3%) were associated with sputum cell sputum, and MM was better. It is not found in the exposed parts of the face and scalp. This is not a good site for sputum cell sputum. Most of the palm and sacral MM are not related to sputum cell sputum. Therefore, some people think that MM is not completely related to sputum cell sputum, but any sputum includes pigmentation. Skin lesions, when sudden growth accelerates, the pigment darkens or becomes light, and irregular pigments appear around it. , or pigmentation loss, itching, tingling, surface scaling, secretion, crusting, ulceration, bleeding, hair loss, satellite nodules in the vicinity, or regional lymph node enlargement with unknown causes should be considered The beginning of the indication of malignant transformation requires careful attention.

2. Ultraviolet radiation

Repeated irradiation of ultraviolet light with a wavelength of 290-320 nm can not only increase the number of melanocytes, but also cause changes in its quality. The incidence of MM is related to the irradiation of sunlight, especially ultraviolet rays. The incidence of MM in southern Norway is almost greater than that in the north. 2 times, according to Israeli statistics, the incidence of agricultural workers MM (15.4/100,000 per year) is higher than that of 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. It is caused by melanocytes in the skin.

3. Ethnic whites have a higher incidence of MM than colored people. 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. Genetic patients are susceptible to this disease in family members. Anderson (1971) reported that 74 of the 22 families were also reported to have identical twins. The age of onset of familial patients was about 10 years earlier, some hereditary. 50% of patients with skin diseases such as xeroderma pigmentosum can develop this disease.

5. Trauma and irritation This disease often occurs in the scalp. The palms and soles often suffer from friction. Many young women often have a history of pointing many years ago. Some people have statistics on 10% to 60% of patients with trauma history, including Bruises, stab wounds, blunt injuries, armor, burns or X-rays.

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

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

(two) pathogenesis

1. Histopathology is a typical melanoma. Under the microscope, melanocytes are abnormally proliferated. Some cell nests are formed in the epidermis or in the epidermis-dermis. These cells are different in size and can be fused to each other. It is seen in the pigmented nevi, the size and shape of the melanocytes in the nest, and the shape of the nucleus have different degrees of variation. Mitosis (including abnormal mitosis) is more common than benign pigmented nevus, and the nucleolus is usually eosinophilic. Bird eye-like, in invasive melanoma, melanoma cells can be seen in the dermis or subcutaneous tissue.

(1) Freckle-like melanoma: In the brown, brown and black areas of the lesion, the morphology of melanocytes in the epidermis varies greatly. In the brown area, the number of melanocytes increases, some cells are normal, and some are more normal cells. Large, some are typical or weird, all cells are distributed along the basement membrane. In the flat black area, many different types of melanocytes replace the basement membrane, forming a band along the epidermal-dermal interface, keratin The cells are located above it, and the dermal papilla layer is below it. At the epidermal-dermal interface, significant pigmentation and keratinized epidermal atrophy are seen, accompanied by extensive atypical melanocyte proliferation, and dense lymphoid tissue in the adjacent dermal papilla. Cells and melanin-rich macrophages infiltrate, and in some areas of the dermis, melanoma cells can be seen to invade, forming large cell nests that correspond to clinically seen nodules.

(2) superficial spreading melanoma: groups of melanocytes are malignant, unlike freckle-like melanoma, melanoma cells are polymorphic, with slightly elevated and pigmented parts of the tumor. Microscopically, there are large melanocytes in the epidermis showing a Pagetoid distribution. These large melanocytes can appear in a single or nest. In the nodule of the tumor, there are dense dermis in the dermis. Tumor cells accumulate, and in the invasive area, large melanocytes are also visible. These cells are rich in cytoplasm and contain fine pigment particles with regular distribution. The whole cells are "dusty"-like changes, occasionally superficial spreading melanoma. The tumor cells are spindle-like.

(3) typical nodular melanoma: tumor cells originate from the epidermis-dermis junction, which can invade the epidermis and dermis upward and downward, respectively, especially in the tendency to invade into the dermis, in the outer area of the invaded epidermis, No atypical melanoma cells can be seen, which can be expressed as epithelial cells or spindle cells.

(4) acne-like sputum-type melanoma: in its plaque area, there is a large melanocyte proliferation in the basal layer, nuclear enlargement, atypical chromatin type, cytoplasm filled with melanin particles, dendritic The mutation is long and can extend to the granular layer. In the area of papules or nodules, the tumor cells are usually fusiform and extend to the dermis.

2. Pathological grading

(1) Grading according to invasion depth: Clark (1969) studied the relationship between the depth of invasion of melanoma and prognosis, and classified the melanoma into 5 grades according to the depth of invasion. The higher the grade, the worse the prognosis.

Grade I: Tumor cells are restricted to the epidermis above the basement membrane.

Grade II: Tumor cells break through the basement membrane and invade the dermal papilla.

Grade III: The tumor cells are filled with the dermal papilla layer and further invade downward, but not to the dermal reticular layer.

Grade IV: Tumor cells have invaded the dermal reticular layer.

Grade V: The tumor cells have passed through the dermal reticular layer and invaded the subcutaneous fat layer.

(2) Vertical thickness grading: Breslow (1970) studied the relationship between the vertical thickness of melanoma and the prognosis. According to the thickest part of the melanoma measured by the eyepiece micrometer (the thickness from the granular layer to the deepest part of the melanoma), it will be black. The tumor is divided into 5 levels:

0.75MM, 0.76~1.50MM, 1.51~3.00MM, 3.01~4.50MM and ?4.50MM, the greater the thickness, the worse the prognosis. This microgradation method was widely used in the future and proved to be important for judging prognosis. value.

Skin malignant melanoma prevention

Try to avoid sun exposure. The use of sun screen is an important primary prevention measure, especially for those at high risk, to strengthen education for the general public and professionals, to improve early morning, early detection, early diagnosis and early treatment, more important .

Skin malignant melanoma complications Complications acute lymphadenitis

Hemorrhagic disease, nodular malignant melanoma progresses rapidly, often local development or metastasis to lymph nodes along the lymphatic vessels, and then transferred to the skin through the blood circulation, visceral causes melaitis, black urine and cachexia, leading to death.

Symptoms of skin malignant melanoma Common symptoms Pigmentation nodules blue, blue-gray or... Claw and nail bed performance... Scaly black urine cell

In situ malignant melanoma

Also known as epidermal darkness, it means that the dark lesions are confined to the epidermis and are in the in situ stage.

(1) malignant freckle-like sputum: also known as Hutchinson freckles, often occurs in older people, almost all seen in the exposed parts, especially the face is the most common, very few can also occur in non-exposed areas, the disease begins as a pigment Uniform spots, generally not uplifted, irregular edges, gradually expanding to the periphery, up to several centimeters in diameter, often expanding on one side, while the other side subsides itself, the damage is light brown, brown, which may be accompanied by dark brown to black spots According to statistics, generally malignant freckles exist for 10 to 15 years, and the area is 4 to 6 cm. Invasive growth occurs later. Therefore, in many cases, especially facial damage, invasive growth is often slow, often invasive. Before sexual growth, the patient died for other reasons.

(2) superficial diffuse in situ malignant: also known as Paget-like in situ black, mostly in middle-aged and elderly patients, can occur in any part, but more common in non-exposed areas, the damage is less than malignant freckle-like sputum, The diameter is rarely more than 2.5cm, often misdiagnosed as sputum cell sputum, usually the skin lesions are slightly bulged, the shape is irregular or the edges are jagged, and some parts are curved, which is characterized by inconsistent tones, yellow-brown, brown, Black, mixed with gray, in the case of invasive growth, its speed is much faster than malignant freckles, often infiltration, nodules, ulcers or bleeding in 1 to 2 years.

(3) acral freckle-like in situ melanoma: the onset may be related to trauma, which is characterized by the onset of palm, sputum, nail bed and hairless parts around the nail bed, especially in the foot, the tumor is in situ The growth time is short, and the invasive growth occurs very quickly. The early manifestations are pigmentation spots with different depths, irregular edges and unclear boundaries. If the lesion is located in the nail and nail bed, it is a longitudinal pigmentation band.

2. Invasive skin malignant melanoma

(1) freckle-like melanoma (freckle-like melanoma): from the invasive growth of malignant freckle-like mites, it is common in the elderly, mostly occurs in the body exposed parts, especially the face, accounting for head and neck melanoma 50% of the lesions are generally circular in shape, usually 3 to 6 cm in diameter or larger, irregularly contoured, flat, color ranging from light brown to black, or black lesions mixed with grayish or light blue areas, with The course of the disease progresses, single or multiple black nodules appear in the lesions. The type of melanoma, which is radiatively grown at the beginning, eventually enters the vertical growth phase, and some do not enter the vertical growth phase at all, so the metastasis occurs later, and the metastasis tends to Local lymph nodes have a 5-year survival rate of 80% to 90%.

(2) Superficial spreading type malignant melanoma is developed from Paget-like in situ black. At this time, local infiltration, nodules, ulcers, and hemorrhage appear on the basis of the original slightly raised patches. This type of melanoma develops faster than freckles, and after a period of radiation growth, it is transferred to the vertical growth phase, and its 5-year survival rate is about 70%.

(3) nodular malignant melanoma (nodular malignant melanoma): can occur anywhere in the body, but most common in the soles of the feet, began to be bulging, dark, blue-black or gray nodules, sometimes pink There are scattered brown melanoma traces around, which will increase soon, and ulcers may occur, or bulge like grass or cauliflower. The type of melanoma progresses rapidly, often without radiation growth period, and directly enters the vertical growth period, 5 years. The survival rate is 50% to 60%.

(4) Special types of melanoma:

1 Acromelic freckle-like nevoid melonoma: The onset may be related to trauma, which is characterized by the onset of palm, sputum, nail bed and nail-free parts around the nail bed, especially in athlete's foot. Clinically similar to freckle-like sputum type melanoma, but more invasive, more common in black and oriental, early manifestations of pigmentation spots of varying depths, irregular edges, unclear boundaries, such as lesions in the claws and The nail bed is characterized by a longitudinal pigmentation band.

2 non-pigmented melanoma (non-pigmented melanoma): relatively rare, accounting for 1.8% of 2881 melanoma reported by Giuliano et al (1982), lesions usually nodular, lack of pigmentation, often delayed diagnosis, prognosis Poor.

3 malignant blue nevus: more rare, caused by malignant transformation of blue sputum cells, common in female buttocks, its obvious feature is that patients can survive for many years even if lymph node metastasis has occurred.

4 malignant melanoma in giant hairy nevus: 30% to 40% of children's melanoma is derived from giant edulis, which is characterized by nodules and ulcers in giant edulis, and color changes. Therefore, congenital giant edema should be closely observed or preventive resection.

5 fibrous proliferated melanoma (probative proliferated melanoma): occurs in the head and neck, nodular growth, about 2 / 3 cases without pigmentation, characterized by a small number of melanoma cells located in a large number of fibrous tissue, The prognosis is poor.

6 melanoma with an unknown primary origin (melanoma with an unknown primary origin): this type of melanoma can not find the primary lesion, melanoma is only found in regional lymph nodes or other organs, the prognosis and the original lesion clear and regional There were no significant differences in lymph node metastasis.

Examination of skin malignant melanoma

1. Histopathological examination shows abnormal proliferation of melanocytes, cell nests in the epidermis or epidermis-dermis, and the nucleolus is usually eosinophilic "bird eye-like", in invasive melanoma, in the dermis or subcutaneous tissue See melanoma cells.

For a typical melanoma, the general HE staining section pathology examination can confirm the diagnosis, but atypical melanoma, such as non-pigmented melanoma, often need to add some special techniques (such as S-100 and HMB-45). Immunohistochemical examination) is helpful for diagnosis.

2. Urine examination When a large amount of melanogen and its metabolites appear in the urine and appear as black urine, it is helpful for the diagnosis of melanoma.

X-ray film, B-ultrasound, CT, MRI and radionuclide scanning tests can help to determine whether the black tumor has lung, liver, kidney, brain and other visceral metastases.

Diagnosis and diagnosis of malignant melanoma of the skin

diagnosis

1. History and symptoms Detailed medical history and physical examination are very important for diagnosis. Any pigmented skin lesions on the body surface, if suddenly increased, there will be pigmentation halo or pigment loss around, scaly, exudation, ulceration, bleeding, hair removal. In the vicinity of satellite nodules, local itching, etc., should consider the occurrence of melanoma.

2. Laboratory examination

(1) Urine examination: Usually laboratory tests are not helpful for diagnosis, but when melanoma has undergone extensive metastasis, a large amount of melanogen and its metabolites may appear in the urine and appear as black urine.

(2) Histopathological examination: to determine the definition of melanoma, the type of tumor, the depth of invasion, the maximum vertical thickness, the cell division phase, whether there is ulcer 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 the presence or absence of regional lymph node metastasis and distant metastasis is important for the development of treatment options and prognosis. Studies have shown that clinical lymph node metastasis is found by palpation. Compared with micrometastasis or subclinial metastasis, the probability of long-term survival is reduced by 20% to 50%. Therefore, it is necessary to determine whether there is lymph node micrometastasis at the early stage. The 5-year survival rate is of great significance.

Differential diagnosis

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

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.