[Reaserch Advance on Langerhans Cell Histiocytosis Review]

Abstract　　Langerhans cell histiocytosis (LCH) is a disease originated from bone marrow dendritic cells, and classified as a tumor by the discovery of a recurrent somatic BRAF-V600E point mutation in the RAS-RAF-MEK-ERK signaling pathway. The clinical manifestations of LCH are mainly granulomatous lesions composed of clonal pathological tissue cells. According to the lesions and invasive risk organs, it is divided into single system diseases, multi-system diseases with risk-free organ infiltration and multi-system diseases with risk organ infiltration. The diagnosis was based on immunohistochemical pathological dendritic cell-specific markers CD1α+⁺and/or CD207⁺,therefore, according to risk stratification, the regiment and intensity of combination chemotherapy and targeted therapy are drawn up. Prognosis is associates with risk organ infiltration, initial treatment response, and BRAF mutations. Due to the low incidence and lack of systematic knowledge, the clinical understanding of this disease is insufficient, thus the rates of misdiagnosis and therapeutic error are high. In this review, the pathogenesis, clinical manifestations, diagnostic and treatment are summarized. So on to provide a theroretical basis for clinical diagnosis and treatment of the diseases.