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

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 lesions of dysplasia are called actinic (photochemically active) keratosis. Photochemical skin lesions due to 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 reddish-brown to red or flesh, and the texture is very rough (like sandpaper). In some of these lesions, so much keratin is produced that the skin horn occurs (see above). 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. These cells have intercellular bridges that are not found in cells of basal cell carcinoma of the skin (see below) with a more basophilic cytoplasm. In actinic keratosis, 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 of the surface layers of the dermis damaged by solar radiation. In addition, they 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.

Other precancerous conditions. These include Bowen's disease (intraepidermal cancer) and Keir erythroplasia. Intraepithelial squamous cell carcinoma of the skin (carcinoma in situ) is manifested macroscopically in the form of clearly limited red flaky plaques. In its microscopic structure (Fig. 25.12, A, B), it resembles carcinoma in situ in other epidermoid epithelial cells (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 open skin areas. 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 carcinogenic substances (contained, in particular, in resins and oils); chronic

Fig. 25.12.

Bowen's Disease

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

A is a form of bovenoid cancer, close to Keyr's erythroplasia

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

The universally recognized exogenous cause of squamous cell carcinoma of the skin is exposure to ultraviolet radiation from the sun, with subsequent damage to D1G and associated mutagenicity. People who suffer from suppressed immunity as a result of massive chemotherapy or after organ transplantation, as well as in patients with xeroderma pigment, there is an increase in the incidence of squamous cell skin cancer. In addition to affecting DNA, sunlight appears 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 processors of epidermocytes (Langerhans cells) in the epidermis. The experiments showed that these cells, which are responsible for the activation of T-lymphocytes, are damaged by ultraviolet radiation, while

Fig. 25.12. Continued.

B -

bovenoid cancer

, proceeding with the phenomena of parakeratosis; AT -

invasive high-grade epidermoid skin cancer

(negatives D. I. Golovin).

similar cells responsible for the selective inclusion of the suppressor lymphocyte system remain resistant to radiation. In humans, such a phenomenon may be accompanied by a local imbalance of T-cell function, which may facilitate the occurrence of a tumor and its progression. 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. They suggest the etiological role of these sequences in the development of certain epithelium of the skin.
Finally, some chemical agents appear to have a direct mutagenic effect, which is realized through the production of DNA adducts with the subsequent activation of oncogenes.

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

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

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

T2 - cancer 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 cancer site, metastases in regional lymph nodes are detected, which are displaced during palpation;

N2 - are determined by palpable displaceable metastases in

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

N3 - unbiased metastases are found in regional lymph nodes on both sides with respect to the primary cancer node;

M1 - there are distant (hematogenous) metastases.

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

Basal cell carcinoma (basal cell carcinoma). This is a very common slow-growing tumor of the epidermis, which rarely metastasizes. It mainly appears in those places that are constantly exposed to solar radiation (especially in people with fair skin). As with epidermoid carcinoma, the incidence of basal cell carcinoma of the skin increases dramatically in persons with reduced immunity and hereditary

Fig. 25.13.

Basal cell carcinoma

(basal cell carcinoma). A is a multifocal form with a superficial type of growth.

defects in replication or DNA repair. The syndrome of a basal cell nevus, rarely occurring and inherited according to the dominant type, is accompanied by multiple basal cell carcinoma, as well as abnormalities in the skeleton, the nervous system, the eyeballs and the reproductive system.

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

Fig. 25.13. Continued.

B -

knotted, solidifying form

; In — form with pronounced potencies for invasion.

Fig. 25.14.

Basalioma differentiating in the direction of the structures of the skin appendages


A - adenoid form; B - trichobasalioma with concentric piloid structures.

a tumor develops from the epidermis or from the lining of hair follicles. Basal cell carcinoma is not found in the mucous membranes.

Two types of growth of this neoplasm are described: multifocal, “emerging” in the epidermis and exciting epidermis of at least a few square centimeters (Fig. 23.13, A), and nodal growth directed inland of the dermis (Fig. 25.13, B, C). In the latter type of growth, strands and complexes of a cancerous parenchyma, constructed of more or less basophilic cells with hyperchromic nuclei, are found. Such complexes can be located in a slightly osliznennaya stroma and are often surrounded by numerous fibroblasts and lymphocytes. The cells bordering the indicated yarns and complexes of the cancer parenchyma are prone to radial location and the formation of palisade figures with their long axes. The stroma of the tumor is often wrinkled, which can create artifacts in the form of gaps between it and the layers of the parenchyma. It helps to distinguish basal cell carcinoma from those tumors of the skin appendages that are accompanied by the proliferation of basaloid cells.

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

Cancer from tactile cells (Merkel cells; KLMerkel). This rare tumor occurs from small and functionally indistinct mechanoreceptors of the epidermis, which are called tactile (tactile) cells (Merkel cells). These cells are derived from the neural crest. In lower animals, they serve the purposes of tactile sensitivity. Merkel cell cancer is a highly malignant neoplasm. The complexes of its parenchyma consist of small round cells containing cytoplasmic granules of neurosecretory type. This rare primary tumor of the epidermis may resemble metastatic small cell carcinoma of the lung (see Chapter 15) or some lymphomas that spread to 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.
    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. Because dysplastic changes are often the result of chronic
  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 orifice 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 orifice 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
Medical portal "MedguideBook" © 2014-2016