Hair follicle sheath acantoma: causes, symptoms, diagnosis, treatment
Last reviewed: 23.04.2024
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The name of the tumor was given to A. Mehregan and M. Brownstein in 1978. Clinically, the tumor has the form of a nodule 0.5-1 cm in size with a central occlusion. The age of the patients is 30-70 years, the frequency in men and women is approximately the same, the localization is the skin of the upper lip, forehead, neck, and the auricles. In this case, most often a diagnosis of comedones, enlarged burrows, cysts, basalomas.
Pathomorphology of the acanthoma of the hair follicle. In the center of the neoplasm is a crater-like widened follicle funnel with a normal lining of epitheliocytes, compact orthokeratosis and hypergranulosis. From the epithelial lining of the funnel radially into the surrounding dermis up to the subcutaneous adipose tissue depart sharply delineated keratinocyte complexes surrounded on the periphery by strips of fibrous tissue giving the complexes a lobate species. On the skin of the face, lobules can penetrate to the level of skeletal muscles. Keratinocytes forming lobules may resemble those of the funnel or the isthmus of the hair follicle. On the periphery, the lobules of the cell are oriented radially. In the central part of each lobule, there are usually cystlike structures delimited by a narrow rim of cells containing granules of keratogialin. Often there are single or small groups of sebaceous cells, scattered necrotic keratinocytes, similar to those in the outer shell of the follicle in the stage of the catagen. Occasionally, rudimentary hair follicles and papillae may occur on the periphery of the complexes.
Differential diagnosis is performed with a solitary keratoacanthoma, which may also have a wide funnel filled with horny masses. However, there are no signs of follicular differentiation in it, and cellular elements can have nuclei with signs of atypia, mitosis figures. At the base of cellular complexes, a thick inflammatory infiltrate, trichophallicoma, is characterized by the presence of a number of well-formed cannon follicles.
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