Dermatoscopic features of monomorphic lesions in cutaneous and indolent systemic mastocytosis; [Дерматоскопические и патоморфологические особенности мономорфных высыпаний при кожном и индолентном системном мастоцитозе]

Introduction. Systematization of dermatoscopic signs of monomorphic rashes in mastocytosis has important practical significance. Aim. To carry out an analysis of dermatoscopic patterns of monomorphic eruption in monomorphic maculopapular cutaneous mastocytosis (mMPCM) and indolent systemic mastocytosis (ISM) and compare the results obtained with pathomorphological signs of mastocytosis. Materials and methods. The study included 6 children aged 4 to 14 years, 27 adolescents and adult aged 15 to 40 years with a monomorphic type of maculopapular cutaneous mastocytosis (MPCM) and 3 patients (minimum age 18 years, maximum – 54 years) with indolent systemic mastocytosis (ISM), who were under observation at Moscow scientific and practical Center of dermatovenereology and cosmetology from 2022 to 2024. Dermatoscopic examination was performed using polarization and immersion dermatoscopy with 20-fold magnification. Results. The presence of mild vascular signs (punctate vessels) and the absence of a pigment pseudonetwork were the features of monoMPCM in children. In adolescents and adults, pigment network was detected in 77.8%, more often in men. The vascular erythematous component in adults was more intense than in children and was detected in 74.1% of patients. Yellow-brown structureless areas, brown reticular lines (pigment pseudonetwork) are due to hyperpigmentation of the basal cell layer, while the vascular pattern was the result of dilation of vessels in the papillary dermis. With ISM, a pronounced vascular pattern (intense erythematous background and reticular vascular pattern) and the obligatory presence of pseudonetwork were observed. The pathomorphological picture of ISM differed from MPCM by the presence of perivascular lymphomonocytic infiltrates and an insignificant number of eosinophilic granulocytes. Conclusion. In this study, age-related dermatoscopic features of monomorphic rashes in mastocytosis were systematized for the first time and compared with the pathomorphological signs of MPCM and ISM. © 2024 Remedium Group Ltd. All rights reserved.