squamous cell carcinoma
Introduction
Introduction to squamous cell carcinoma Squamous cell carcinoma (squamous cell carcinoma) is abbreviated as squamous cell carcinoma. It originates from the skin epidermis and its appendages (hair follicle funnel, sebaceous gland duct, terminal sweat tube) keratinocytes, which occur in exposed parts such as the scalp, face, neck and back of the hand. Can be ulcers, and often secondary to chronic ulcers or chronic sinus openings, or ulcers in the scars are cancerous after prolonged unhealed. Clinically, it can be cauliflower-like, irregular edge bulge, uneven bottom, easy to bleed, often accompanied by infection and stench. There may be local infiltration and regional lymph node metastasis. In the lower extremities are often accompanied by osteomyelitis or periostitis. basic knowledge The proportion of sickness: 0.002%-0.003% Susceptible people: men who are more than 50 years old Mode of infection: non-infectious Complications: osteomyelitis periostitis
Cause
Squamous cell carcinoma
Long-term exposure to sunlight (19%):
In 1948, Blum proved that the carcinogenic ray is a part of the solar spectrum with a wavelength of 290-320mm. The ultraviolet rays in the sun invade the human body, causing DNA damage in the cells and destruction of its repair ability, resulting in skin cancer. The melanin in the skin can protect the skin from skin. UV damage, this is the reason why white people are vulnerable to UV damage and skin cancer, and their habit of sunbathing is also one of the reasons for the high incidence of ozone. The ozone layer on the earth becomes thinner and forms an ozone hole, causing too much Ultraviolet radiation can cause an increase in skin cancer patients.
Chemical stimulation (18%):
Some chemical substances such as arsenic and asphalt can cause skin squamous cell carcinoma. The incidence of skin squamous cell carcinoma in workers exposed to asphalt is about 12 times higher than that of ordinary workers, such as asphalt, coal tar, paraffin, and compounds containing arsenic. Carcinogenicity, especially leading to squamous cell carcinoma.
Human papillomavirus (15%):
Human papillomaviruses, especially types 16, 18, 30 and 33; immunosuppression, organ transplantation is also an important factor in induction.
Genetic factors (10%):
Genetics is also an important disease factor. Some hereditary skin diseases such as pigmented dry skin disease, albinism and other colored squamous cell carcinomas have higher incidence than whites. Domestic Sun Shaoqian and other reports reported 191 skin cancers in 1956. Among them, squamous cell carcinoma accounted for 78.5%, while Germany's Bosenberg reported in 1953 that 133 cases of skin cancer accounted for only 15% of squamous cell carcinoma.
(1) Causes of the disease
Since Perceval Pott first reported in 1775 that chimney sweepers had scrotal squamous cell carcinoma due to exposure to soot, the pathogenesis of squamous cell carcinoma has been noted. Many virulence factors can induce squamous cell carcinoma, mainly for long-term exposure to ultraviolet light, followed by Radiation damage, thermal damage, carcinogenic chemicals such as arsenic, polycyclic aromatic hydrocarbons, coal tar, creosote, paraffin, hydrazine, tobacco tar, chromate, etc. are closely related to the occurrence of squamous cell carcinoma.
1. Precancerous skin diseases Some precancerous skin diseases such as sun keratosis, leukoplakia, arsenic keratosis, X-ray and radium dermatitis are prone to squamous cell carcinoma, and other chronic skin diseases such as sacral epidermal development Poor, chronic ulcers, chronic sinus, chronic osteomyelitis, chronic lupus erythematosus, lupus vulgaris, atrophic sclerosing moss, etc. can induce or secondary squamous cell carcinoma.
2. Excessive radiation exposure on the basis of chronic dermatitis, such as exposure to excessive radiation, can also cause cancer of the skin, long-term exposure to radiation, such as lack of protective measures, can also induce skin cancer.
3. Scars A variety of traumatic scars, especially burn scars are more likely to develop squamous cell carcinoma.
4. secondary to chronic skin diseases, such as lupus, lupus erythematosus, mucosal leukoplakia, chronic ulcer or sinus, burn scar, radiation dermatitis, chronic granuloma, epithelial dysplasia, chronic osteomyelitis, atrophy Sclerosing moss can induce or secondary squamous cell carcinoma.
(two) pathogenesis
1. Histopathological findings There are roughly three types of cancer cells:
(1) Differently differentiated spine cells: Unlike normal spine cells, tumor cells are large in size, polygonal in shape, short fusiform or irregular in shape, rich in cytoplasm, intercellular bridge, eosin staining, uneven, and inner Glycogen-containing, cells are transparent and vacuolated; the size and staining of the nucleus are different, with multinuclear, megakaryocytes and more mitotic figures.
(2) Keratinized cells: single or clustered clusters, keratinized beads appear in the center of cancer cell mass, composed of keratinized substances arranged in a concentric layer (such as onion), large nuclei, deep stained, cytoplasm Dark red, showing eosinophilic, complete or incomplete keratinization, which is a characteristic structure of squamous cell carcinoma.
(3) Undifferentiated or poorly differentiated spindle-shaped cells: the cell volume is small and the cytoplasm is less; the nucleus is deeply stained, and there is no reticular fiber between the cells.
The above several cancer cells are often intermingled and arranged in a papillary, nested, strip-like or pseudo-adenoid structure (Fig. 1).
2. Squamous cell carcinoma generally differentiates well, and highly differentiated squamous cell carcinoma accounts for about 75%. The cancer cells are papillary, nested, cord-like or adenoid, and can be infiltrated into the dermis or subcutaneous tissue according to the degree of differentiation of cancer cells. Level 4:
(1) Grade I: differentiated mature squamous cell carcinoma with intercellular bridge and cancer beads. Cancer beads are characteristic structures of squamous cell carcinoma and are composed of concentrically arranged angular cancer cells.
(2) Grade II: with spine cells as the main component, and has obvious heteromorphism, including the enlargement of cancer cells, the size of the nucleus, the different shades of staining, the more common nuclear division, the fewer cancerous beads, and the central horn Incomplete.
(3) Grade III: poor cell differentiation, most of the cells in the surface of the skin are disordered, the cell volume is enlarged, the nuclear shape is obvious, the nuclear fission is more common, and there is no cancerous bead, but some cells are keratinized, and the lesion is in the epidermis. Radial expansion, infiltration of the dermis is later.
(4) Grade IV: undifferentiated, no spine cells, no intercellular bridge and cancerous beads, the cancer is finely fusiform, the nucleus is slender and stained deeply, and there are necrotic and pseudo-adenoid structures, a few are squamous cells and Keratinocytes can be used as a basis for diagnosis.
3. Broders classification According to the percentage of undifferentiated cells in cancer cells, invasive squamous cell carcinoma is divided into four grades.
(1) Grade I: tumor tissue does not exceed the level of sweat glands, undifferentiated cells <25%, more angular beads.
(2) Grade II: Undifferentiated cells <50%, only a few angular beads, less keratinocytes in the center of the bead, a little more atypical cells, and unclear boundaries of cancer cells.
(3) Grade III: undifferentiated cells <75%, no horns, large keratinized cells, dark red cytoplasm, deep nuclear staining, mitotic figures and atypical;
(4) Grade IV: undifferentiated cells >75%, keratinized, atypical tumor cells, no intercellular bridge, difficult to diagnose.
The greater the proportion of undifferentiated cells, the higher the degree of malignancy. In addition, the depth of invasion is also an important factor in estimating the degree of malignancy. In low-grade squamous cell carcinoma, rare cancer cells invade below the sweat glands. organization.
According to Broders classification, squamous cell carcinoma is mostly grade I or II with higher differentiation, and grade III or IV with low differentiation is rare.
Prevention
Squamous cell carcinoma prevention
Squamous cell carcinoma is a highly malignant tumor with a very poor prognosis. Prevention is mainly for possible induced causes. Removal of pathogenic factors and incentives is the key to prevent this disease. Usually pay attention to avoid excessive sun exposure and ultraviolet rays, X-ray irradiation, and frequent contact. Chemical substances such as arsenic and asphalt should be actively treated and regularly examined for long-term chronic ulcers or leukoplakia, which will help prevent the occurrence of squamous cell carcinoma.
Complication
Squamous cell carcinoma complications Complications osteomyelitis periostitis
As the tumor develops, it may be accompanied by damage to the cartilage, muscles, bones, etc., and may be transferred to the lymph nodes.
1. Infected ulcer is the main clinical feature of squamous cell carcinoma. It is often preceded by chronic ulcer and infection. It can also be infected after cancer. When infected, the necrotic tissue is decomposed to produce malodor.
2. When osteomyelitis or periostitis squamous cell carcinoma infiltrates deep, it may involve deep skeletal tissue and cause osteomyelitis or periostitis.
Symptom
Squamous cell cancer symptoms common symptoms papules scaly scars crescentic osteolytic defects epidermal keratinized squamous epithelial chronic ulcer
Men who are more than 50 years old, common in the face, scalp, lower lip, back of the hand, forearm, genitals, etc., especially at the junction of skin and mucous membranes, the beginning is dark red hard, small nodules, surface capillary The blood vessels are dilated, the horny objects are attached in the center, and it is not easy to be peeled off. After peeling off, the skin lesions can be gradually enlarged, and the skin lesions gradually enlarge, forming hard red patches, a little scale on the surface, clear borders, infiltration into the surroundings, hard touch, rapid expansion. Ulcers, ulcers invade to the surrounding and deep, can reach the muscles and bones, damage each other to form a hard mass, not easy to move, the base of the ulcer is meat red, necrotic tissue, pus, odor, easy bleeding, ulcer edge Uplifted valgus, obvious inflammation, conscious pain, such as occurs at the junction of skin and mucous membranes, solid moisture and friction are more likely to bleed, develop faster, can form cauliflower-like, destructive, obvious pain, easy to metastasize, poor prognosis.
Early skin lesions often have small, hard reddish nodules with unclear borders and smooth surfaces, but often evolve into warts or papillomas, sometimes with scales on the surface, and progressive tumor enlargement.
According to the speed of tumor development, ulcers will occur sooner or later in the tumor center. The rapidly developing tumors will have ulcers before the diameter of 1-2 cm. The surface of the ulcer is granular, with necrotic tissue, easy to bleed, and the edge of the ulcer is wide and high. Hard, with stench, 90% of squamous cell carcinoma that occurs in the lips occurs in the lower lip (Figure 3), often a single nodular ulcerative lesion, which develops faster than skin squamous cell carcinoma, with poor prognosis, generally secondary to Radiation dermatitis, tar keratosis, scars, ulcers, sinus, its metastasis is much higher than sun damage, such as solar keratosis; occurs in the lips, penis, female genital is also easy to transfer.
Primary squamous cell carcinoma is rare, early is a small papule, nodular or sacral, reddish, rough surface, rapid growth and easy to rupture and infiltrate into the periphery, more common in the top of the head, secondary squamous cell carcinoma See, often caused by cancer on the basis of chronic ulcers, scars and other damage on the original scalp.
Examine
Squamous cell carcinoma examination
Visual observation: the shape is irregular, the texture is hard, no capsule, no boundary with the surrounding tissue, the profile is substantial, grayish white, and the center often has necrotic areas.
Microscopic examination: The morphology and structure of tumor cells are the same as those of other squamous cell carcinomas. In the middle and high differentiation, intercellular bridges and keratinized beads can be seen; poorly differentiated keratinization is not obvious, no mucous cells, and no glandular structure .
Histopathological examination of tumors consists of irregular epidermal cell masses that proliferate to the dermis, which are composed of different proportions of normal squamous cells and atypical (metamorphic) squamous cells. Atypical squamous cells vary in size and shape. Nuclear proliferation, deep staining, atypical nuclear fission, disappearance of intercellular bridges, local keratinization and angular bead formation (tumor cells arranged in concentric circles, incomplete or completely keratinized from the periphery to the center) The higher the malignant degree of the tumor, the lower the degree of cell differentiation, the less the formation of the horns, the less the intercellular bridge, the less inflammatory reaction in the dermis, and the higher the cell differentiation, the intercellular bridge, the more horns, the dermis The inflammatory response is heavy.
Diagnosis
Diagnosis and differentiation of squamous cell carcinoma
Squamous cell carcinoma should be differentiated from benign chronic ulcer and tuberculous ulcer. It should be similar to basal cell carcinoma in early stage. It should be associated with melanoma, keratoacanthoma, pigmented nevus, radiation ulcer, photokeratosis and other malignant skin tumors. It is differentiated from diseases such as granuloma, and can be identified based on clinical manifestations, especially histopathological examination.
Histopathologically, it should be differentiated from pseudocarcinomatous hyperplasia, which is found in chronic proliferative inflammation. The tissue resembles a primary or secondary squamous cell carcinoma, but squamous cells usually differentiate well, atypical such as individual cell corners. In addition, the proliferation of nuclear proliferation is mild or absent. In addition, common leukocytes invade the hyperplastic epidermis, causing some epidermal cells to disintegrate, while squamous cell carcinoma does not. This requires the use of multiple biopsies combined with clinical identification.
