Squamous cell carcinoma of the skin

Squamous cell carcinoma (synonym: spinal cell carcinoma, squamous epithelioma, spinalomy) is an invasive tumor with the presence of squamous cell differentiation. Can occur in any part of the body, but especially exposed open areas exposed to insolation; in addition, often occurs on the lower lip. Squamous cell carcinoma also occurs on the external genitalia and in the perianal region. This is the most malignant tumor of all epithelial skin newly formed.

Squamous cell carcinoma of the skin occurs predominantly in the elderly, equally common in men and women.

According to the scientific literature, squamous cell carcinoma of the skin often occurs against the background of pathological changes in the skin: precancerous diseases, for example, prekankrenozny cheilitis Manganotti), focal-cicatricial atrophy, on scars after burns, injuries. In the WHO classification (1996), the following variants of squamous cell carcinoma are indicated: spindle cell, acantholytic, verruzed with formation of cutaneous horn, lymphoepithelial.

There is a squamous cell carcinoma of the skin that develops against actinic keratosis, and squamous cell carcinoma that occurs in the scar tissue, on the site of burns, mechanical damage or chronic inflammation (lupus tuberculosis of the skin, late x-ray dermatitis, etc.). These differences are based mainly on the propensity of the tumor to megastasis.

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What causes squamous cell carcinoma?

Squamous cell carcinoma can occur on the background of actinic keratosis, post-burn scar tissue, permanent mechanical injuries, chronic inflammatory dermatosis such as hypertrophic forms of red flat lichen, tuberculosis, lupus, xeroderma, etc. The squamous cell carcinoma that develops on the sun damaged skin , in particular, foci of actinic keratosis, metastasizes rarely (0.5%), whereas the frequency of metastasis of squamous cell carcinoma that occurs on scars, inserts more than 30%, and in the foci of late X-ray dermatitis - about 20%.

Histopathology and pathomorphology of squamous cell carcinoma of the skin

Histologically distinguish between corneal and non-coronary forms of squamous cell carcinoma. With the keratinized form, the growth of epithelial cords is marked, expressed by polymorphism, discomplexation and dyskeratosis of individual cells ("horny pearls").

Distinguish keratinizing and non-keratinous squamous cell carcinoma. In both forms, the tumor consists of randomly arranged complexes of atypical cells of flat epithelium with invasive growth into the dermal layers of the dermis and subcutaneous tissues. The degree of cellular atypia can be different and is characterized by changes in the size and shape of the cells themselves, their nuclei, changes in the nuclear-cytoplasmic ratio, the presence of polyploid forms, pathological mitoses. Differentiation of cells occurs with the phenomena of excessive keratinization, which is accompanied by the appearance of so-called horny pearls - foci of hyperkeratosis of round shape with signs of unfinished keratinization in the center, keratogialin granules are few or absent.

In non-corroborating squamous cell carcinomas, epithelial cells with pronounced polymorphism are detected, the boundaries of which are difficult to determine. The cells have a different shape and size and small hyperchromic nuclei. There are pale core-shadows and nuclei in a state of decay. Mitosis, usually pathological, is often detected.

A. Broders (1932) established four degrees of malignancy of squamous cell carcinoma depending on the ratio of mature (differentiated) and immature cells in the tumor, as well as the degree of their atypia and the depth of infestation.

At I degree, cell strains penetrate the dermis to the level of the sweat glands. The basal layer in places with disorganization phenomena is indistinctly separated from the surrounding stroma. In tumor strands, differentiated flat-epithelial cells predominate with well-developed intercellular bridges, some of them with signs of atypia. "Horny pearls" quite a lot, some of them in the center with the completed process of keratinization, in the dermis around the tumor a significant inflammatory reaction.

II degree of malignancy is characterized by a decrease in the number of differentiated cells, "horny pearls" are few, the process of keratinization in them is not completed, there are quite a few atypical cells with hyperchromic nuclei.

At the third degree, the keratinization process is almost completely absent, keratinization is observed only in separate groups of cells with a weakly eosinophilic cytoplasm. Most tumor cells are atypical, many mitoses.

For the fourth degree of malignancy, there is a complete absence of signs of keratinization, almost all tumor cells are atypical without intercellular bridges. Inflammation in the stroma is very weak or absent altogether. To distinguish such an undifferentiated, anaplastic tumor from melanoma or sarcoma, a panel of monoclonal antibodies, including cytokeratins, S-100, HMB-45 and markers of lymphocytic (LCA) cells, should be used.

The study of inflammatory infiltrate in squamous cell cancer with histological, histochemical and immunological methods showed that in growing and metastasizing tumors T-lymphocytes, natural killers, macrophagocytes and tissue basophils are detected, the degranulation of which is observed both in the tumor itself and in the stroma.

In addition to the forms of squamous cell carcinoma described above, the following histological types of skin are distinguished: acanthotic, boweloid, spindle cell. The acanthotic type (syn: carcinoma spinocellulare segregans, pseudoglandulare spinaliom) develops more often in the elderly on the basis of actinic keratosis. A histological study of this type shows that tumor complexes and strands are degraded, transformed into tubular and pseudo-alveolar structures lined with one or more rows of atypical cells; Keratinization is not always observed. Occasionally, such cavities are detected by acantholytic or discrete cells.

The Bowenoid type of squamous cell carcinoma is characterized by a pronounced polymorphism of the nuclei and the absence of "horn pearls" in tumor strands. Dyskeratosis and poikilocytosis are sharply expressed.

The spindle cell type of squamous cell carcinoma is characterized by the presence of structures consisting of spindle cell elements, can resemble sarcoma, has no clear histological signs of keratinization, has more pronounced infiltrating growth, more often recurs and metastasizes, differs less favorable prognosis. However, when using electron microscopy, the epithelial origin of this type of cancer is proved on the basis of the detection of tonofilaments and desmosomes in cancer cells.

Histogenesis of squamous cell carcinoma of the skin

Proliferation and the lack of differentiation of epithelial elements in squamous cell carcinoma occur as a result of a violation of tissue regulation and malignant autonomy of their functions. The importance of the state of the immune system of antitumor surveillance for the onset and development of the tumor process, in particular squamous cell cancer, clearly demonstrates the fact that the frequency of basal cell and squamous cell carcinoma is 500 times higher in patients with organ transplant receiving immunosuppressive therapy than in human populations similar age-dependent. In pathogenetic terms, in addition to immunosuppression, a clear correlation between the occurrence of squamous cell carcinoma, the actinic factor and the oncogenic cofactor of the effects of human papillomavirus 16 and 18 is revealed.

Symptoms of squamous cell carcinoma of the skin

Clinically squamous cell carcinoma of the skin, as a rule, is a solitary knot, but can be plural. Exo-and endophytic forms of growth are distinguished. In exophytic form, the tumor node rises "above the skin level, has a broad base, dense consistency, is inactive, often covered with hyperkeratotic layers." In the endophytic (ulcerative, ulcerative-infiltrating) form, the initial nodule quickly undergoes ulceration with the formation of an irregularly shaped ulcer with a craterial bottom. The periphery of it can form daughter elements, the decay of which increases the size of the ulcer.The tumor becomes immobile, it can destroy surrounding tissues, including bones, with The deep form of squamous cell carcinoma can occur with pronounced inflammatory phenomena, which makes it similar to the pyogenic process.There is a verruque form in which the tumor is covered with warty growths, grows slowly, rarely metastasizes.In old age, more often in men, squamous cell carcinoma can manifest itself in the form of a cutaneous horn.

An important role in the oncogenesis of squamous cell carcinoma of the skin, especially when the process is localized in the anogenital region, is the human papillomavirus virus of the 16th and 18th types.

Distinguish between neoplastic and ulcerative skin cancer. At the beginning of the disease, a papule appears surrounded by a corolla of hyperemia, which for several months turns into a dense (cartilaginous consistency), soldered to the subcutaneous fatty tissue, a sedentary node (or plaque) of reddish-pink color, with a diameter of 1.5 cm or more, with scales or warty growths on the surface (warty variety), easily bleeding at the slightest touch, necrotic and ulcerating.

With papillomatous variety, more rapid growth is noted, individual elements are on a wide base, having the form of cauliflower or tomato.

Tumors often ulcerate at 4-5 months of existence.

With a ulcerous type, irregularly shaped ulcers with distinct edges are formed, covered with a brownish crust. The ulcer extends not in depth, but in the periphery. With a deep form, the process spreads both to the depth and to the periphery. In this case, the ulcer has a dark red color, steep edges, a hilly bottom, a yellowish white coating.

Differential diagnosis

Squamous cell carcinoma of the skin should be distinguished from pseudoepithelioma hyperplasia, basal cell carcinoma, Bowen's disease.

Differential diagnosis of skin cancer is carried out with precancerous conditions, which are observed with actinic keratosis, skin horn, warty dyskeratosis, pseudocarcinomatous hyperplasia, keratoacanthoma, etc.

With undifferentiated form, cells with hyperchromic nuclei predominate. In this case, keratinization is not observed or is weakly expressed.

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Treatment of squamous cell carcinoma of the skin

Surgical removal of the tumor is performed within healthy tissues. Applied also cryodestruction, photodynamic therapy. The choice of method of treatment depends on the prevalence and localization of the process, the histological picture, the presence of metastases and the age of the patient. Tumor removal is often combined with X-ray therapy.