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Precancerous conditions and malignant tumors of the epidermis



Actinic keratosis. Almost always, before malignancy, dysplastic changes appear in the epidermis; there is an analogy with the stages of development of squamous cervical cancer. Since dysplastic changes are often the result of chronic exposure to sunlight and are associated with the formation of excess keratin, foci of dysplasia are called actinic (photochemically active) keratosis. Photochemical skin lesions by solar radiation are especially common in people with fair skin. Similar changes are caused by ionizing radiation, some hydrocarbon compounds and arsenic. Skin lesions are usually less than 1 cm in diameter. Their color varies from tan to red or flesh, and the consistency is very rough (like sandpaper). In some of these lesions, so much keratin is produced that skin horn occurs (see above). More often exposed areas of the skin are affected: the face, forearms and the back of the hands. The same lesions sometimes occur on the lips (actinic cheilitis).

With actinic keratosis, cellular atypia is noted mainly in the lower layers of the epidermis. It can be associated with hyperplasia of the cells of the basal layer or, conversely, with early atrophy, leading to a diffuse decrease in the thickness of the epidermis in the neoplasm zone. Atypical basal cells, as a rule, have signs of dyskeratosis, as well as pink or reddish cytoplasm. These cells have intercellular bridges, which are not found in cells of basal cell carcinoma of the skin (see below) with a more basophilic cytoplasm. With actinic keratosis, the dermis contains thickened elastic fibers (dermis elastosis), which is regarded as a possible violation of the production of elastic fibers by fibroblasts of the surface layers of the dermis damaged by solar radiation. In addition, a thickening of the stratum corneum is noted, in contrast to normal skin, the nuclei in the cells of this layer are preserved. The nature of actinic keratosis is unknown. It is very likely that many such skin changes regress or remain stable throughout life. However, a large number of them are malignant, which justifies surgical excision.

Other precancerous conditions. These include Bowen's disease (intraepidermal cancer) and Keir erythroplasia. Intraepithelial squamous cell carcinoma of the skin (carcinoma in situ) appears macroscopically in the form of clearly defined red scaly plaques. In its microscopic structure (Fig. 25.12, A, B), it resembles carcinoma in situ in other epidermoid type epithelia (see chapters 7, 16 and 21). The same can be said about Keir erythroplasia.

Squamous cell carcinoma of the skin. In older people, squamous cell carcinoma is the most common tumor among those that occur in exposed areas of the skin. With the exception of the skin of the distal lower extremities, these neoplasms are more common in men. In addition to solar radiation, factors predisposing to malignancy are also: industrial carcinogens (contained, in particular, in resins and oils); chronic



Fig. 12/25.

Bowen's disease

(carcinoma in situ, bowenoid cancer) and flat cell skin cancer.

A - a form of bovenoid cancer, close to Keir erythroplasia

skin ulcers; draining osteomyelitis; scars after burns; skin absorption of arsenic compounds; exposure to ionizing radiation. People with xeroderma pigmentosa (see Chapter 7), immunocompromised individuals also have a higher incidence of squamous cell skin cancer (compared to healthy people).

The generally recognized exogenous cause of squamous cell carcinoma of the skin is the exposure to the ultraviolet part of solar radiation, followed by damage to D1G and the associated mutagenicity. People whose immunity is suppressed as a result of massive chemotherapy or after an organ transplant, as well as in patients with xeroderma pigmentosa, have an increase in the incidence of squamous skin cancer. In addition to its effects on DNA, sunlight seems to have a direct or at least transient immunosuppressive effect on the skin. Apparently, ultraviolet rays act on the normal control function of antigen-presenting white adolescent epidermocytes (Langerhans cells) in the epidermis. In experiments, it was shown that these cells responsible for the activation of T-lymphocytes are damaged by ultraviolet radiation, while



Fig. 12/25. To be continued.

B -

form of bowenoid cancer

proceeding with the phenomena of parakeratosis; AT -

invasive highly differentiated epidermoid skin cancer

(negatives of D.I. Golovin).

similar cells responsible for the selective incorporation of the suppressor lymphocyte system remain radiation resistant. In humans, this phenomenon may be accompanied by a local imbalance in T-cell function, which may facilitate the onset of a tumor and its progression. The DNA sequences of certain viruses (e.g., human papillomavirus HPV36) have recently been found in DNA extracted from potential squamous cell progenitor cells. The etiological role of these sequences in the development of certain skin epitheliomas is suggested.
Finally, some chemical agents appear to have a direct mutagenic effect, which is realized through the development of DNA adducts with subsequent activation of oncogenes.

Invasive skin cancer is accompanied by keratinization to varying degrees (see. Fig. 25.12, C) and may be ulcerated. Skin cancer is characterized by varying degrees of histological differentiation.

The stages of the spread of skin cancer through the TNM system are as follows:

T1 - a tumor with a diameter of up to 2 cm has exophytic and superficial growth;

T2 - a cancerous node with a diameter of 2-5 cm germinates the dermis;

T3 - neoplasm more than 5 cm in diameter or deeply growing in the dermis;

T4 - the tumor grows into the underlying tissues (muscles, cartilage or bone tissue);

N1 - on the side of the primary cancerous node, metastases in the regional lymph nodes that are displaced by palpation are detected;

N2 - palpatory metastases are determined in

lymph nodes either only on the side opposite to the location of the tumor, or on both sides;

N3 - non-biased metastases are detected in regional lymph nodes on both sides with respect to the primary cancerous node;

M1 - there are distant (hematogenous) metastases.

Only about 5% of cases of invasive skin cancer are accompanied by metastases to regional lymph nodes.

Basal cell carcinoma (basal cell carcinoma). This is a very common slowly growing epidermal tumor that rarely metastases. Basically, it appears in those places that are constantly exposed to solar radiation (especially in people with fair skin). As with epidermoid cancer, the incidence of basal cell skin cancer increases sharply in people with reduced immunity and hereditary



Fig. 25.13.

Basal cell carcinoma

(basal cell carcinoma). A is a multi-focal form with a surface type of growth.

defects in DNA replication or repair. Rarely encountered and inherited by a dominant type, basal cell nevus syndrome is accompanied by multiple basal cell carcinoma, as well as abnormalities in the skeleton, nervous system, eyeballs and reproductive system.

Externally, basal cell carcinoma is a papule with a pearly tint, in which dilated blood vessels (telangiectasia) are defined under the epidermis. Sometimes a tumor contains melanin and may resemble a non-cellular nevus or melanoma. The tumor may be ulcerated (ulcus rodens - an ulcer with superficial erosion). In addition, in the absence of treatment, an extensive local invasion develops. Histologically, the elements of the tumor parenchyma resemble cells of the basal layer of the epidermis. Parenchyma



Fig. 25.13. To be continued.

B -

nodal, solidified form

; B - a form with pronounced potentials for invasion.



Fig. 25.14.

Basal cell carcinoma differentiating to the structures of the appendages of the skin

.

A is an adenoid form; B - trichobazalioma with concentric piloid structures.

Tumors develop from the epidermis or from the lining of the hair follicles. Basal cell carcinoma does not occur in the mucous membranes.

Two types of growth of this neoplasm are described: multi-focal, “incipient" in the epidermis and exciting epidermis with an area of ​​at least several square centimeters (Fig. 23.13, A), and nodular growth directed deep into the dermis (Fig. 25.13, B, C). With the latter type of growth, strands and complexes of the cancer parenchyma, constructed from more or less basophilic cells with hyperchromic nuclei, are found. Such complexes can be located in a slightly mucous stroma and are often surrounded by numerous fibroblasts and lymphocytes. Cells bordering these strands and cancer parenchyma complexes are prone to radial arrangement and the formation of palisade figures with their long axes. The stroma of the tumor is often shrunken, which can create artifacts in the form of gaps between it and the layers of the parenchyma. This helps to distinguish basal cell carcinoma from tumors of the appendages of the skin that are accompanied by proliferation of basaloid cells.

The histological differentiation of basal cell carcinoma in the direction of the structures of the appendages of the skin is also well known: adenoid basal cell carcinoma (Fig. 25.14, A), trichobazalioma, containing piloid (hair-like) structures (Fig. 25.14, B), and other (sometimes combined) forms.

Cancer from tactile cells (Merkel cells; KLMerkel). This rare tumor originates from small and functionally indistinct epidermal mechanoreceptors, which are called tactile (tactile) cells (Merkel cells). These cells belong to derivatives of the neural crest. In lower animals, they serve the purpose of tactile sensitivity. Merkel cell cancer is a very malignant neoplasm. The complexes of its parenchyma consist of small round cells containing cytoplasmic granules of the neurosecretory type. This rare primary epidermal tumor may resemble metastatic small cell lung carcinoma (see chapter 15) or some lymphomas that spread to the dermis.

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Precancerous conditions and malignant tumors of the epidermis

  1. Precancerous conditions and malignant tumors of the epidermis.
    Precancerous skin conditions - actinic keratosis, cutaneous horn, Bowen's disease, Keir erythroplasia. Actinic keratosis. Almost always, before malignancy in the epidermis, dysplastic changes appear, similar to changes in other organs lined with stratified squamous epithelium, for example, in the cervix. Because dysplastic changes are often the result of chronic
  2. TUMOR GROWTH. TUMOR PROGRESSION. TUMOR MORPHOGENESIS. INVASION AND METASTASIS OF MALIGNANT TUMORS. BIOMOLECULAR TUMORS MARKERS. ANTITUMOR IMMUNITY. PARANEOPLASTIC SYNDROMES. BASIC PRINCIPLES OF CLASSIFICATION OF TUMORS. MORPHOLOGICAL FEATURES OF TUMORS FROM EPITELIUM AND TUMORS FROM TISSUES - DERIVATED MESENCHIMES
    TUMOR GROWTH. TUMOR PROGRESSION. TUMOR MORPHOGENESIS. INVASION AND METASTASIS OF MALIGNANT TUMORS. BIOMOLECULAR TUMORS MARKERS. ANTITUMOR IMMUNITY. PARANEOPLASTIC SYNDROMES. BASIC PRINCIPLES OF CLASSIFICATION OF TUMORS. MORPHOLOGICAL FEATURES OF TUMORS FROM EPITELIUM AND TUMORS FROM TISSUES - DERIVATIVES
  3. Background and precancerous conditions
    Most malignant ovarian tumors develop against the background of previous benign tumors. Therefore, all true benign ovarian tumors should be considered as precancerous conditions. Ovarian tumors more often develop in women with a certain premorbid background. Women with this background should be classified as a risk group for the development of ovarian tumors (background conditions).
  4. Precancerous conditions
    Precancerous conditions of the cervix (dysplasia) is a pronounced proliferation of atypical cervical epithelium with a violation of its “stratification” (stratification) without involving the stroma and surface epithelium in the process. Therefore, dysplasia is a histological term recommended by WHO (1976) instead of many other names for this pathology: atypia, cervical intraepithelial neoplasia
  5. Precancerous conditions of the cervix
    Types of precancerous conditions of the cervix: 1) Cervical erosion is a red area on the cervix, clearly delimited from the surrounding pale pink surface, and located around the opening of the cervical canal. There is true and pseudo-erosion. Cervical ectopy is usually not accompanied by any symptoms. Extensive ectopia sometimes causes an increased amount of mucous discharge
  6. Precancerous conditions of the cervix
    Types of precancerous conditions of the cervix: 1) Cervical erosion is a red area on the cervix, clearly delimited from the surrounding pale pink surface, and located around the opening of the cervical canal. There is true and pseudo-erosion. Cervical ectopy is usually not accompanied by any symptoms. Extensive ectopia sometimes causes an increased amount of mucous discharge
  7. Pigmentation disorders. Pathology of the melanocytic system of the epidermis. Melanocytic tumors
    Melanocytes are located in the basal layer of the epidermis. Their number varies in different parts of the skin. Melanocytes synthesize melanin in specialized organelles - melanosomes, tyrosinase is involved in this process. This enzyme catalyzes the conversion of tyrosine to dioxiphenylalanine (DOPA), which is converted into melanin during other biochemical reactions. Melanosomes spread along them,
  8. Malignant tumors
    SARCOM is a malignant tumor from the mesenchymal tissue. Unlike sarcoma cancer, the first metastases are hematogenous. Histogenesis sarcomas are divided into a number of varieties. From fibrous tissue. 1. Fibrosarcoma. 2. Swelling dermatofibroma (malignant histiocytoma) - unlike other sarcomas, it is characterized by slow growth and for a long time does not give metastases, although it grows
  9. Malignant tumors
    Malignant tumors of the nose and paranasal sinuses take third place in frequency among other malignant lesions of the upper respiratory tract (larynx and pharynx) and, according to published data, comprise 2 - 3% of malignant tumors of all localizations. Malignant tumors most often develop in the maxillary sinus. In second place in frequency are lattice maze tumors.
  10. Malignant Epithelial Tumors
    They are called cancer, or carcinoma. General characteristics. 1. Meet much more often than all other malignant tumors. 2. Often associated with previous diseases and conditions, which are called precancerous. 3. The development of many carcinomas (morphogenesis) is associated with previous changes in the epithelium - hyperplasia, metaplasia, dysplasia. 4. The only precancerous
  11. Malignant tumors
    In the upper respiratory tract, cancer is mainly found in various forms and rarely (about 3% in relation to malignant tumors of the ENT organs)
  12. Malignant pharyngeal tumors
    The comparative incidence of pharyngeal cancers is high; carcinomas, lymphoepitheliomas, cytoblastomas, sarcomas, reticulocytomas, and mixed tumors are found among them. Men get sick more often than women, usually in middle age. K l and n and with to and to kartin and. The early symptoms of pharyngeal malignant tumors are poor and little characteristic. Light sensations may appear.
  13. Malignant tumors of the nose and paranasal sinuses
    Malignant diseases of this localization - cancer and isarcoma, as a rule, are primary. They are relatively rare, more often in middle-aged and elderly men. Most often, the primary malignant process affects the maxillary, then ethmoid, frontal and sphenoid sinuses. Rarely, the source of the malignant tumor is the nasal septum. Malignancy
  14. Malignant tumors of the ear
    Malignant tumors of the ear can be both primary, i.e. developed directly in a particular department of the ear, and arising from the germination of tumors from neighboring organs and tissues. In the outer and middle ear, cancer is more often diagnosed in adults, and sarcoma in children. Of the other species, there may be melanoma. The course of tumors of the outer ear is relatively slow, they look like
  15. Malignant tumors of the vulva and vagina
    Vulvar cancer (RV) is found mainly in elderly women and accounts for 3-5% of all malignant diseases of the genitals. It develops against the background of involutive dystrophic processes. An important role in the occurrence of this pathology is given to metabolic and endocrine disorders and viral infection. Classification of PB by stages • Stage 0 - pre-invasive carcinoma. • Stage I - tumor up to 2
  16. Malignant skin tumors
    There are many theories of cancer (embryonic, virogenetic, hereditary, somatic mutations, etc.). Malignant tumors are characterized by infiltrating growth with destruction of the surrounding tissue and metastasis. Различают два типа рака кожи: базально - клеточный и плоскоклеточный. Базалиома, или базально - клеточный рак, встречается преимущественно у лиц пожилого возраста.
  17. ЗЛОКАЧЕСТВЕННЫЕ ОПУХОЛИ КИШЕЧНИКА
    — это обладающие автономным (не всегда) прогрессирующим необратимым характером роста патологические разрастания атипичных клеток, которые замещают и инфильтрируют нормальную ткань. Классификация Стадии рака 1 стадия — опухоль небольших размеров, локализуется в толще слизистой или подслизистом слое, без метастазов; 2 стадия: а) опухоль больших размеров, но не более полуокружности
  18. ЗЛОКАЧЕСТВЕННЫЕ ОПУХОЛИ МОЛОЧНОЙ ЖЕЛЕЗЫ И БЕРЕМЕННОСТЬ
    Среди злокачественных новообразований у женщин рак молочной железы занимает одно из первых мест. За последние годы увеличилась частота сочетания беременности и рака. Выделяют два аспекта этой проблемы: рак среди беременных и беременность при раке. Рак молочной железы у беременных встречается в 0,03—0,3 % случаев, беременность при раке молочной железы — в 0,78—3,8 %, а в отдельных сообщениях
  19. МАЛОКРОВИЕ ПРИ ЗЛОКАЧЕСТВЕННЫХ ОПУХОЛЯХ И МНОЖЕСТВЕННЫХ ИХ МЕТАСТАЗАХ В КОСТНЫЙ МОЗГ
    Причиной анемического состояния при злокачественных опухолях могут быть следующие факторы: 1) токсическое воздействие злокачественной опухали на эритропоэз; 2) кровотечения вследствие распада опухоли и разрыва сосудов; 3) вторично присоединяющаяся инфекция; 4) расстройство эритропоэза вследствие метастазов в костный мозг; 5) ахилия (при раке желудка) и связанное с ней нарушение усвоения
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