Ultrastructure of Dyskeratosis in Morbus Darier

Abstract

Biospy specimens from three patients with morbus Darier were studied by electron microscopy: Grains appeared in groups in the midst of dyskeratotic lesions and were recognized as being the result of more advanced acantholysis and precocious keratinization. Corps ronds were formed individually in the regions lateral to that of grains, where hypergranulosis was prominent in contrast to a mild dyskeratosis. Therefore, the formation of grains and corps ronds seem to be independent of each other. While in the literature acantholysis has mainly been ascribed to the separat;on of desmosones into two segments, another initial process seems to be the primary disappearance of the attachment plaque along with the connecting tonofilaments. From the existence of the other contact complexes, it seems likely that a restoration of desmosomes between acantholytic cells should take place. In early stages of dyskeratotic cells, keratinosomes were increased in number and some of them persisted inside the plasma membrane without a release into the intercellular spaces, and thus they were present in grains and corps ronds. The dyskeratosis in morbus Darier is characterized by a premature, incomplete and individual keratinization as evidenced by the existence of keratohyalin granules and keratinosomes as early as at the level of the 3rd epidermal layer and the absence of a keratin pattern in the dyskeratotic horny cells.

Ultrastructural localization of cell junctional components (desmoglein, plakoglobin, E‐cadherin, and β‐catenin) in Hailey‐Hailey disease, Darier's disease, and pemphigus vulgaris

“…Many ultrastructural studies of Hailey-Hailey disease and Darier's disease have demonstrated detachment of tonofilaments from desmosomes (28,29) and splitting of desmosomes {30-33). Some authors have observed intracytoplasmic desmosomes (30,34). We found intracytoplasmic desmosomes in either disease so rarely that they can not account for the diffuse immunofluorescence of desmosomal components found in the cytoplasm in acanthoiytic cells.…”

Dissociation of intra- and extracellular domainsof desmosomal cadherins and E-cadherin inHailey-Hailey disease and Darier’s disease

“…Disruption of desmosome–keratin filament complexes in keratinocytes on electron microscopy has been demonstrated in previous studies on lesional skin specimens from HHD and DD patients. 6–12 In both of these diseases, abnormal distributions of desmosomal proteins have been shown by immunohistochemistry and immunoelectron microscopy, although no apparent loss of expression has been detected. 13–22 These results suggest that abnormalities in cell adhesion structures, including desmosomes and adherens junctions, result in a disruption of cell adhesion in HHD and DD.…”

Darier's disease of the oral mucosa: clinical case report with ultrastructural evaluation

“…Although it is possible that reattaehment of cells occurs at higher levels, no evidence of such is apparent. Sato et al (1977) associated attachment plaques without tonofilaments between cells with cellular reattachment. Since adjacent epithelial mucosa appears normal, it is possible that cells from this mucosa migrated above the acantholytic area.…”

“…Such changes as nuclear pyknosis and cytoplasmic vacuolation of the spiny layer cells as described by Gottlieb & Lutzner (1973) and Mann & Haye (1970) were not seen in our lesions at LM or EM levels. Sato et al (1977Sato et al ( , 1978 investigated earlier reports of accelerated cell renewal in Darier's disease. They used electron microscopic and light mictoscopic autoradiographic (H-' thymidinc) methods and concluded that there is an increased cell turnover rate as well as precocious keratin formation in skin.…”