Langerhans cell histiocytosis as a clonal disease of mononuclear phagocyte system

Langerhans cell histiocytosis (LCH) belongs to histiocytic proliferative diseases, which are rare in clinical practice; however they pose significant challenges both for their diagnosis and choice of therapeutic strategies. Histiocytic proliferative diseases are the scope of oncology; nevertheless, at the diagnostic stage the patients are referred to pediatricians or dermatologists. That is why the interdisciplinary interaction of various specialties and common approaches to their classification, diagnosis and treatment are important for the management of patients with histiocytic proliferative disorders. Accumulation of the studies on the LCH patho-physiology has promoted the development of new diagnostic algorithms and treatment methods. After the fact of MAPK signal pathway activation had been established, the potential target for therapy was identified. Neoplastic nature of LCH has been hypothesized. If confirmed, we can expect actual diagnostic algorithms being elaborated, in particular, the potential to predict the disease depending on the tumor clone mutation type. The unique characteristics of LCH including proliferate clonality (presumable of neoplastic nature), the disease course with spontaneous regression and frequent relapses and tropism to certain tissues (target organs) make up the grounds for further in-depth studies of the disease. © 2022, Moscow Regional Research and Clinical Institute. All rights reserved.