Porokeratosis

Porokeratosis unites a group of diseases characterized by a violation of keratinization.

Porokeratosis is a disease inherited by autosomal dominant. Several clinical variants of pokeratosis, differing in grouping, quantity and location of vysypnyh elements are described: Mibelli's porokeratosis, characterized by single elements. Located predominantly on the limbs: surface disseminated eruptive rikeratosis of Reschighi, which is characterized by multiple foci of lesion developing in childhood; linear, unformed (or zosteriform) porokeratosis, usually found on the limbs and reminiscent of a linear prostucous nevus; disseminated surface actinic beetrokeratosis, which appears more often in adults after solar irradiation and localized in open areas of the body; point-like porokeratosis, characterized by diffuse eruptions on the fingers, palms and soles; palmar-plantar and disseminated pufferatosis in the form of numerous rashes in the beginning on the palms and soles, then on the trunk and extremities. Three more variants are described - discrete botterokeratosis of soles with single or multiple conical papules reminiscent of plantar warts, reticular porokeratosis with erythematous rash in the form of a mesh localized to the trunk and disseminated bilaterial hyperkeratotic variant of Mibelli's porokeratosis.

[1], [2], [3], [4], [5], [6], [7], [8],

Causes of the bACKGROUND

Porokeratosis is a hereditary disease transmitted autosomal dominantly with reduced penetrance. The state of immunosuppression, immune-suppressive diseases, in particular AIDS, ultraviolet irradiation can cause or exacerbate the drug. In lesions, dysplasia of varying severity, the formation of pathological clones of cells that are more sensitive to ultraviolet irradiation than surrounding free cells are detected. In the cultured fibroblasts, chromosome 3 is unstable, which increases the risk of skin neoplasia. In the literature there is a description of family cases.

[9], [10], [11], [12],

Pathogenesis

In the central part of the element, there is an invagination of keratin into the epidermis in the form of a cone, sometimes capturing its entire thickness. In the center of intussusception in the horn masses, the parakeratotic column (plate) is seen - a characteristic sign of the disease. Under the column, a granular layer is absent, but, in general, this layer is thinned. In the dermis - vasodilation, perivascular lymphohistocaric infiltrates.

Pathomorphology

All described clinical variants of porekeratosis are characterized by the same histological pattern. The main histological sign is the formation of the horny plate in the deepening of the epidermis filled with horny masses, which is a column of parakeratotic cells. Deepening may be located at the mouth of the sweat gland, at the mouth of the hair follicle and intraphollicularly. Under the column of parakeratotic cells, there is no granular layer, there are vacuolated discrete cells. In the epidermis of hyperkeratosis, acanthosis and papillomatosis are noted around the horny plate. Vacuum degeneration of Malpighian cells is possible. In the derma under the basal membrane, a nonspecific lymphocytic infiltrate with single plasma cells is detected. With superficial actinic Bockeratosis, along with the features described, thinning of the Malpighian layer, vacuolar degeneration of basal epitheliocytes, and superficial band-shaped infiltrate with basophilic dystrophy of collagen are noted. N. Inamoto et al. (1984) observed in necrotic epithelial cells and eosinophilic spongiosis. Electron microscopy revealed that the horny plate consists of two types of cells. Some of them are similar in shape to spiny cells and contain a pycnotic nucleus, bundles of tonofilaments of different density, melanosomes, as well as remnants of organelles, others have a rounded shape, are devoid of desmosomes, and resemble discrete cells in their structure. On the periphery of the horny plate are flat cells containing a substance close to normal keratin, and structures with a low electron density, reminiscent of organelles. In cells under the horny plate, the number of granules of keratogialin and tonofilament significantly reduced. Among such cells were rounded cells, in structure resembling "round bodies" in Darya's disease. Part of spiny cells under the horny plate underwent partial or complete destruction, they contain pycnotic nuclei, vacuoles, hetero- and autophagosomes, and aggregated along the periphery of the wall, the tonofilaments. The intraepithelial destruction of epithelial cells is pathognomonic for pokeratosis and can serve as a diagnostic sign. In the basal layer, intercellular edema and reduplication of the basal membrane are noted locally. In the state of dystrophy there are also dermal fibroblasts, some of them contain phagocytosed collagen fibers. There is a degeneration of collagen fibers.

[13], [14], [15], [16]

Histogenesis

The formation of the roto-shaped plate occurs, according to some authors, as a result of two processes: intra-epidermal cell destruction (apoptosis) and dyskeratosis-type keratinization disorders. T. Wade and A.V. Ackerman (1980), in the formation of the horny plate, the main importance is attached to inflammatory changes in the dermis, S. Margheseu et al. (1987) - microcirculatory disorders, and R. Heed and P. Leone (1970) suggested that the basis of the histogenesis of Bockeratosis is the appearance of a clone of altered epithelial cells at the base of the parakeratotic column forming the horny plate. The process of destruction of spiny cells is compensated by a certain increase in the mitotic activity of basal epitheliocytes. The imbalance of mitotic activity and apoptosis is the cause of malignancy in the foci ofkerokeratosis, as well as the appearance of mutant epitheliocytes. Pathological ploidy of DNA, a neoplastic clone in epidermal cells were detected. It has been suggested that Bockeratosis is not only an epidermal anomaly. Perhaps its development is due to the pathology of the two embryonic sheets.

Symptoms of the bACKGROUND

There are several clinical variants of Bockeratosis.

Clinically, for all variants of porekeratosis, one and the same morphological element is characteristic: annular plaques of various sizes with a sinking atrophic center and an elevated hyperkeratotic narrow margin with a groove on the surface. The development of this element begins with the formation of a keratotic papule, gradually increasing in size, forming an annular plaque, after regression which remains the site of skin atrophy. The elements localized on the palms and soles differ somewhat in appearance. Thus, in case of point-like pokeratosis, they are small indentations 1-3 mm in diameter filled with keratin, with discrete plantar porekeratosis - conical papules resembling plantar warts. Sometimes there are atypical rashes - hyperkeratotic, verruzed, ulcerative, exudative and giant. The possibility of a combination of different clinical variants of the drug from the same patient confirms the commonality of their pathogenesis.

Combinations of porokeratosis and psoriasis are described. There are frequent cases of malignant tumors such as squamous cell carcinoma, basalioma and Bowen's disease in patients with pukokeratosis, which makes it possible for some authors to consider it a precancerous disease. Malignant growth usually begins in the area of the atrophic center of ring-shaped plaques.

[17], [18], [19], [20], [21], [22], [23], [24], [25]

Classical Bovine Fiberate

The disease is more common in children, but can develop at any age. The initial element is the horny papule, which due to eccentric growth increases in size and turns into an annular plaque. Eruptions are usually few, plaques of various sizes - from a few millimeters to several centimeters, round in shape. The central part of the element looks sunken, dry, slightly atrophic, sometimes de- or hyperpigmented, warty or with hyperkeratosis. In the peripheral zone of the lesion, a raised keratotic roller (curb) is clearly visible. At close examination by means of a magnifier on a surface of a border it is possible to see a characteristic sign - parallel and pair rows of a hyperkeratosis located.

Foci of lesion are more often located on the body, arms, legs. Genitalia, the mucous membrane of the oral cavity and the cornea can be affected.

[26], [27], [28], [29], [30], [31]

Disseminated surface actinic granulomatosis

It is more common in the third or fourth decade of life in areas of the skin exposed to sunlight. Usually the lesions are multiple and, according to the clinical picture, reminiscent of the classic Mibeli's pufferosis. However, with actinic ponokeratosis on the curb surface, parallel, pairwise rows of hyperkeratosis are often not detected.

[32], [33], [34], [35], [36], [37]

Palmar-plantar and disseminated BACKGROUND

A rare form of Bockeratosis and more common in adults. The disease begins with the appearance on the palms and soles of numerous small, slightly elevated, papules or plaques. Then the foci spread to other parts of the body. With this kind of pokeratosis, the predisposition of lesions to be localized on body parts exposed to sunlight is not noted. However, in 25% of patients, exacerbation of the disease is observed in the summer.

Linear Bockeratosis

Usually begins in childhood. Multiple papules of rounded shape, located unilaterally, linearly, segmentally or zosteriformally on the trunk or extremities, often along the Blaschko line, appear. In the clinical picture, linear BACKERATOR is very similar to the epidermal nevus. Described are erosive and ulcerative variants of the course of linear canceratosis on the face.

The course of Bockeratosis

The disease has existed for many years, but cases of spontaneous resolution have been described. In all cases of clinical course, the skin process can be transformed into a neoplastic one.

Differential diagnosis

Differential diagnosis is carried out with psoriasis, red lichen planus, warts, basaliomas, ring-shaped granuloma, discoid lupus erythematosus, seborrhoea and horny eczema and epidermal nevi.

Treatment of the bACKGROUND

Assign keratolytic funds, cryodestruction, intraocular injection of corticosteroids, 5% ointment of 5-fluorouracil; with actinic form - photoprotective creams; when common forms are recommended, aromatic retinoids or large doses of vitamin A