[Histiocytoses: General classification and molecular criteria]

Histiocytoses are rare and heterogeneous disease sharing histology, characterized by accumulation of histiocytes. They may be inherited or sporadic, and related to the accumulation of endo- or exogenous material in macrophages or to macrophage activation. Recent discoveries have shown that some histiocytoses, such as Langerhans cell histiocytosis or Erdheim-Chester disease, previously considered as idiopathic or inflammatory were clonal myeloid proliferations. This review presents the general classification of histiocytoses, and describes diagnostic and molecular criteria of idiopathic histiocytoses and histiocytic neoplasms.