the main
about the project
Medicine news
To authors
Licensed books on medicine
<< Ahead Next >>

Pre-cancerous conditions and malignant tumors of the epidermis.

Pre-cancerous conditions of the skin - actinic keratosis, cutaneous horn, Bowen's disease, Keir erythroplasia.

Actinic keratosis. Almost always, before malignancy, dysplastic changes appear in the epidermis, similar to changes in other organs lined by stratified squamous epithelium, for example, in the cervix. Since dysplastic changes are often the result of chronic exposure to sunlight, they are called actinic (photochemically active) keratosis. Photochemical skin lesions due to solar radiation are especially common in people with fair skin. Similar changes cause ionizing radiation, some hydrocarbon compounds and arsenic. Skin lesions are usually less than 1 cm in diameter. Their color varies from reddish-brown to red or flesh, and the texture is very rough (like sandpaper). Some of these lesions produce so much keratin that a skin horn occurs (see below). Often affects open skin: face, forearm and back of the hands. The same lesions sometimes occur on the lips (actinic cheilitis).

In actinic keratosis, cellular atypia occurs mainly in the lower layers of the epidermis. It may be associated with hyperplasia of the cells of the basal layer or, conversely, with early atrophy, which leads to a diffuse decrease in the thickness of the epidermis in the area of ​​the tumor. Atypical basal cells, as a rule, have signs of dyskeratosis, as well as pink or reddish cytoplasm. The dermis contains thickened elastic fibers (elastosis of the dermis), which is regarded as a possible violation of the production of elastic fibers by fibroblasts damaged by solar radiation. Note the thickening of the stratum corneum, in contrast to the normal skin of the nucleus in the cells of this layer are preserved. The nature of actinic keratosis is unknown. It is very likely that many of these skin changes will regress or remain stable throughout life. However, a large number of them are malignized, which justifies surgical excision.

Cutaneous horn (acrohordon, horny keratoma) is a squamous benign tumor of the skin in the form of a conical or linear dark formation consisting of dense horny masses. Occurs more frequently in exposed areas of the body. Microscopically at the base of the corneous masses acanthic growths of the epidermis are expressed, in the underlying lymphatic lymphohistiocytic infiltration

Bowen's disease is characterized by the fact that changes are localized everywhere, often on the skin of the genitals, eyelids and torso. It is regarded as intraepithelial (intraepidermal) squamous cell carcinoma (carcinoma in situ) and is a clearly limited red scaly plaque, perhaps their ulceration. Microscopically characterized by hyper- and parakeratosis, acanthosis, there are multinuclear giant cells, large ovoid cells (pedzhetovy), atypical mitoses. The intercellular bridges are preserved. In the underlying dermis pronounced lymphohistiocytic infiltration. With long-term existence, invasive growth is possible with the development of poorly differentiated epidermoid cancer.

Erythroplasia Keira, like Bowen's disease, is considered as intraepithelial cancer. Microscopically characterized by thinning of the granular and horny layers of the epidermis, the presence of acantotic cords deeply penetrating into the tissue, represented by polymorphic cells with a small number of mitoses. Abundant lymphoplasmacytic infiltration on the background of a sharp expansion of blood vessels is noted around acanthosis sites.

Squamous cell carcinoma of the skin. In older people, squamous cell carcinoma is the most common tumor among those that occur in open skin areas. This neoplasm is more common in men. In addition to solar radiation, factors predisposing to malignancy are: industrial carcinogens (contained, in particular, in resins and oils); chronic skin ulcers; drainage osteomyelitis with the presence of skin fistulas; scars after burns; skin absorption of arsenic compounds; exposure to ionizing radiation. People with pigmented xeroderma and immunocompromised persons are at a higher risk than squamous cell carcinoma of the skin than healthy ones.

The generally recognized exogenous cause of squamous cell carcinoma of the skin is the exposure of ultraviolet rays of the sun to keratinocytes with DNA damage. Sunlight, apparently, also has a direct immunosuppressive effect on the skin, disrupting the normal control function of the antigen presenting growth cells of Langerhans. The DNA sequences of certain viruses (for example, human papillomavirus HPV36) have recently been found in DNA extracted from potential precursors of squamous cell carcinoma.
Thus, the appearance of skin tumors can contribute to chronic viral infection. Finally, some chemical agents have a direct mutagenic effect, which is realized through the production of DNA adducts with the subsequent activation of oncogenes.

Invasive skin cancer is associated with keratinization to varying degrees and may be ulcerated. Histologically, squamous cell carcinoma is characterized by layers of atypical polymorphic epithelium, and the intercellular bridges are preserved. Cancer with keratinization or without keratinization, spindle cell carcinoma, clear cell carcinoma of the adenoid type (with gland-like structures) are distinguished.

Skin cancer is characterized by various degrees of histological differentiation and stages according to the TNM system (Table 37.11).

Only about 5% of cases of invasive skin cancer are accompanied by metastases to the regional lymph nodes, with tumor progression the cancer metastasizes by the lymphogenous and hematogenous pathways.

Basal cell carcinoma (basal cell carcinoma) is the most common skin tumor. It has a pronounced infiltrating growth, often recurs, but, as a rule, does not metastasize, therefore, it is more correct to include it in the group of tumors with localized growth. Basically, it appears in those places that are constantly exposed to solar radiation (face and neck), it is plural. It occurs with the same frequency in persons of both sexes, mainly in old age. The incidence of basal cell carcinoma of the skin increases dramatically in persons with reduced immunity (for example, after immunosuppressive therapy) and in the presence of defects in DNA repair.

The tumor is represented by a pearly-colored plaque, sometimes pigmented. The tumor may ulcerate with the formation of extensive deep ulcers (ulcus rodens - an ulcer with superficial eroding). Microscopically characteristic polymorphic

Table 37.11 Stages in the spread of squamous cell carcinoma of the skin through the TNM system

T1 - tumor up to 2 cm in diameter has exophytic and superficial growth
T2 - cancer node with a diameter of 2-5 cm germinates in the dermis
TK - neoplasm more than 5 cm in diameter or deeply germinating in the dermis
T4 - the tumor grows into the underlying tissues (muscle, cartilage or bone)
N1 - on the side of the primary cancer site, metastases are found in the regional lymph nodes, which are displaced on palpation
N2 - palpable displaceable metastases in the lymph nodes are determined either only on the side opposite to the tumor, or on both sides
N3 - non-displaceable metastases in regional lymph nodes on both sides in relation to the primary cancer node
M1 - there are distant (hematogenous) metastases
cords and complexes of small, intensely stained cells resembling cells of the basal layer of the epidermis, having a prismatic along the periphery of the cord, in its thickness - a polygonal shape. There are mitosis. In typical cases, the phenomenon of "accumulation", i.e. clusters and cords of tumor cells "slip" from the basal layers of the epithelium, as if penetrating drops into the dermis.

The superficial multicentric type of basal cell carcinoma (characterized by multiple cell strands growing into the dermis), scleroderm-like (with sclerosis and hyalinosis of the stroma), fibroepithelial types, and basal cell carcinoma are distinguished: adenoid, characterized by the formation of glandular and cystic structures; licked; pigmented; trichobazalioma (contains piloid or hair-like) structures; basal squamous cell carcinoma.

Cancer from tactile cells (Merkel cells). This rare tumor originates from small mechanoreceptors of the epidermis, which are derived from the neural crest and are called tactile (tactile) cells (Merkel cells). Merkel cell cancer is a very malignant neoplasm, most often localized to the head and neck and gives early distant metastases. The neoplasm parenchyma consists of complexes of small round cells containing cytoplasmic granules of neurosecretory type. This primary tumor of the epidermis may resemble metastatic small cell carcinoma of the lung or some lymphomas occurring with a lesion of the dermis.

<< Ahead Next >>
= Go to tutorial content =

Pre-cancerous conditions and malignant tumors of the epidermis.

  1. Pre-cancerous 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 cell carcinoma of the cervix uterus. Since dysplastic changes are often the result of chronic exposure to sunlight and are associated with the formation of an excess amount of keratin, the foci of dysplasia are called actinic (photochemical
  3. Background and precancerous conditions
    Most of the malignant tumors of the ovaries develop against the background of previous benign tumors. Therefore, all true benign ovarian tumors should be considered as precancerous conditions. Ovarian tumors often develop in women with a certain premorbid background. Women with this background should be considered at risk for the development of ovarian tumors (background conditions).
  4. Precancerous conditions
    Pre-cancerous conditions of the cervix (dysplasia) is a pronounced proliferation of the atypical epithelium of the cervix with a violation of its “lamination” (stratification) without involvement of the stroma and superficial epithelium in the process. Consequently, dysplasia is a histological term recommended by WHO (1976) instead of many other names for this pathology: atypia, cervical intraepithelial neoplasia
    Types of cervical precancerous conditions: 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. It happens true and pseudo. Ectopia of the cervix is ​​usually not accompanied by any symptoms. Sometimes extensive ectopia causes an increased amount of mucous secretions.
    Types of cervical precancerous conditions: 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. It happens true and pseudo. Ectopia of the cervix is ​​usually not accompanied by any symptoms. Sometimes extensive ectopia causes an increased amount of mucous secretions.
  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 dioxyphenylalanine (DOPA), which is converted into melanin during other biochemical reactions. Melanosomes spread through them,
  8. Malignant tumors
    SARCOMA is a malignant tumor from mesenchymal tissue. Unlike cancer of sarcoma, the first metastasis is hematogenous. Histogenesis sarcomas are classified into a number of varieties. From fibrous tissue. 1. Fibrosarcoma. 2. Bulging dermatofibroma (malignant histiocytoma) - unlike other sarcomas, it is characterized by slow growth and does not metastasize for a long time, although it grows
  9. Malignant tumors
    Malignant tumors of the nose and paranasal sinuses occupy the third place among other malignant lesions of the upper respiratory tract (larynx and pharynx) and constitute, according to literary data, 2-3% of malignant tumors of all localizations. Malignant tumors most often develop in the maxillary sinus. In the second place in frequency are tumors of the ethmoid labyrinth.
  10. Malignant epithelial tumors
    They are called cancer, or carcinoma. General characteristics. 1. It is much more common than all other malignant tumors. 2. Often associated with previous diseases and conditions that are called precancerous. 3. The development of many carcinomas (morphogenesis) is associated with previous changes in the epithelium - hyperplasia, metaplasia, dysplasia. 4. The only pre-cancerous
  11. Malignant tumors
    In the upper respiratory tract mainly cancer is found in various forms and is rare (about 3% in relation to malignant tumors of the upper respiratory tract)
  12. Malignant tumors of the pharynx
    The comparative incidence of malignant tumors of the pharynx 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 c e to and I to and r t and N and. The early symptoms of malignant tumors of the pharynx are poor and not very characteristic. Light sensations may appear.
  13. Malignant tumors of the nose and paranasal sinuses
    Malignant diseases of this localization - cancer isarcoma, as a rule, are primary. They are relatively rare, often in middle-aged and elderly men. Most often, the primary malignant process affects the maxillary, then the ethmoid, frontal and sphenoid sinuses. Rarely, the nasal septum is the source of a malignant tumor. Malignancy
  14. Malignant ear tumors
    Malignant tumors of the ear can be as primary, i.e. developed directly in this or that part of the ear, and arisen during the germination of tumors from neighboring organs and tissues. In the outer and middle ear, adults are more often diagnosed with cancer, in children - sarcoma. Of other types, there may be melanoma. The course of the tumors of the external ear is relatively slow, apparently they resemble
  15. Malignant tumors of the vulva and vagina
    Cancer of the vulva (PB) occurs mainly in older women and is 3-5% of all malignant diseases of the genitals. Develops against the background of involutive dystrophic processes. An important role in the occurrence of this pathology is attached to metabolic and endocrine disorders and viral infection. RV classification by stages • Stage 0 - preinvasive carcinoma. • Stage I - tumor up to 2
  16. Malignant skin tumors
    There are many theories of cancer (embryonic, virusogenetic, hereditary, somatic mutations, etc.). Malignant tumors are characterized by infiltrating growth with destruction of the surrounding tissue and metastasis. There are two types of skin cancer: basal cell and squamous. Basal cell carcinoma, or basal cell carcinoma, occurs predominantly in the elderly.
  17. Malignant tumors of the intestine
    - pathological growths of atypical cells that have autonomous (not always) progressive irreversible growth pattern that replace and infiltrate normal tissue. Classification Stages of cancer Stage 1 - a tumor of small size, localized in the thickness of the mucosa or submucosal layer, without metastases; Stage 2: a) a tumor of large size, but not more than a semicircle
  18. Malignant mammary gland tumors and pregnancy
    Among the malignant tumors in women, breast cancer is one of the first places. In recent years, the frequency of combinations of pregnancy and cancer has increased. Two aspects of this problem are distinguished: cancer among pregnant women and pregnancy in cancer. Breast cancer in pregnant women occurs in 0.03–0.3% of cases, pregnancy in breast cancer - in 0.78–3.8%, and in separate reports
  19. Low incidence in malignant tumors and their multiple metastasis to the bone marrow
    The following factors may be the cause of the anemic state in malignant tumors: 1) the toxic effect of the malignant tumor on erythropoiesis; 2) bleeding due to disintegration of the tumor and rupture of blood vessels; 3) re-joining infection; 4) Erythropoiesis disorder due to bone marrow metastases; 5) Akhiliya (in case of stomach cancer) and an associated disorder of absorption
  20. Malignant tumors of the larynx
    Malignant tumors
Medical portal "MedguideBook" © 2014-2016