Histiocytic disorders are a diverse group of diseases that arise from the abnormal proliferation and accumulation of histiocytes, which are a type of immune cell derived from the monocytic lineage. These cells are part of the mononuclear phagocyte system and include macrophages and dendritic cells. In histiocytic disorders, these cells can accumulate in various tissues and organs, leading to a range of clinical manifestations.
