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Persistent lenticular keratosis: causes, symptoms, diagnosis, treatment
Last reviewed: 07.07.2025
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Keratosis persistent lenticularis (syn. Flegel's disease) refers to a group of hereditary diseases with a predominant disorder of keratinization, the type of inheritance is autosomal dominant. Men and women are equally often affected. The first manifestations of the disease are observed at the age of 40-50 years in the form of reddish-brown small papules measuring 1-4 mm, covered with scales, irregular in shape, localized on the back of the feet, upper and lower extremities. When removing the scales, a shiny bottom of the funnel with pinpoint bleeding is exposed. The rash is sometimes accompanied by slight itching. Combined with diabetes mellitus.
Pathomorphology. In the center of the lesion, thinning of the epidermis is noted, along the edges - acanthosis and papillomatosis. The stratum corneum is mostly compact, significantly thickened, especially in the center of the element, where focal parakeratosis is also detected. The granular layer is absent in the atrophic areas of the epidermis. The basal epithelial cells are flattened, edematous, the basal membrane of the epidermis is unclear. In the papillary layer and the upper part of the reticular layer of the dermis, the vessels are dilated, a dense infiltrate of a lymphohistiocytic nature is determined, clearly delimited from the underlying layers of the dermis. In the horny scales, electron microscopic examination of the skin in the atrophy zone reveals light threads in a dense matrix, preservation of desmosomes. Parakeratotic cells, a decrease in the number of keratohyaline granules are detected. In the granular epithelial cells and the absence of lamellar granules in them. Lymphocytes with cerebriform nuclei were found in the infiltrate.
Histogenesis. Great importance is attached to the pathology of lamellar granules, which play an important role in the differentiation of epithelial cells. However, unambiguous data on their changes have not yet been obtained. Based on the detection of macrophage lipid cells and lymphocytes with cerebriform nuclei in the infiltrate, the role of immune reactions in the development of the disease is assumed.
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