RT info:eu-repo/semantics/article T1 Cd34+ Stromal Cells/Telocytes in Normal and Pathological Skin A1 González Gómez, Miriam A1 Díaz-Flores, Lucio A1 Gutiérrez, Ricardo A1 García, Maria Pino A1 Rodríguez-Rodriguez, Rosa A1 Hernández-León, Nieves A1 Díaz-Flores, Lucio Jr. A1 Carrasco, José Luís A2 Grupo de investigación: Neurobiología Humana. K1 stromal cells K1 telocytes K1 skin histology K1 non-tumoral skin pathology K1 skin tumors K1 CD34 AB We studied CD34+ stromal cells/telocytes (CD34+SCs/TCs) in pathologic skin, afterbriefly examining them in normal conditions. We confirm previous studies by other authors inthe normal dermis regarding CD34+SC/TC characteristics and distribution around vessels, nervesand cutaneous annexes, highlighting their practical absence in the papillary dermis and presencein the bulge region of perifollicular groups of very small CD34+ stromal cells. In non-tumoralskin pathology, we studied examples of the principal histologic patterns in which CD34+SCs/TCshave (1) a fundamental pathophysiological role, including (a) fibrosing/sclerosing diseases, such assystemic sclerosis, with loss of CD34+SCs/TCs and presence of stromal cells co-expressing CD34 andαSMA, and (b) metabolic degenerative processes, including basophilic degeneration of collagen, withstromal cells/telocytes in close association with degenerative fibrils, and cutaneous myxoid cystswith spindle-shaped, stellate and bulky vacuolated CD34+ stromal cells, and (2) a secondary reactiverole, encompassing dermatitis—e.g., interface (erythema multiforme), acantholytic (pemphigus,Hailey–Hailey disease), lichenoid (lichen planus), subepidermal vesicular (bullous pemphigoid),psoriasiform (psoriasis), granulomatous (granuloma annulare)—vasculitis (leukocytoclastic andlymphocytic vasculitis), folliculitis, perifolliculitis and inflammation of the sweat and sebaceousglands (perifolliculitis and rosacea) and infectious dermatitis (verruca vulgaris). In skin tumorand tumor-like conditions, we studied examples of those in which CD34+ stromal cells are (1) theneoplastic component (dermatofibrosarcoma protuberans, sclerotic fibroma and solitary fibroustumor), (2) a neoplastic component with varying presentation (fibroepithelial polyp and superficialmyxofibrosarcoma) and (3) a reactive component in other tumor/tumor-like cell lines, such as thosederiving from vessel periendothelial cells (myopericytoma), epithelial cells (trichoepithelioma, nevussebaceous of Jadassohn and seborrheic keratosis), Merkel cells (Merkel cell carcinoma), melanocytes(dermal melanocytic nevi) and Schwann cells (neurofibroma and granular cell tumor). YR 2021 FD 2021 LK http://riull.ull.es/xmlui/handle/915/35023 UL http://riull.ull.es/xmlui/handle/915/35023 LA en DS Repositorio institucional de la Universidad de La Laguna RD 26-jun-2024