title: Histiocytoses: emerging neoplasia behind inflammation.
abstract: Histiocytoses are disorders characterised by inflammation and the accumulation of cells derived from the monocyte and macrophage lineages, which results in tissue damage. Although they are often considered rare disorders with protean clinical manifestations, considerable advances in the understanding of their genetics have led to increased clinical recognition of these conditions, and fuelled further insights into their pathogenesis. In this Review, we describe insights into the cells of origin, molecular pathology, clinical features, and treatment strategies for some of the most common histiocytic disorders, including Langerhans cell histiocytosis, Erdheim-Chester disease, and Rosai-Dorfman disease. With the discovery of recurrent mutations affecting the mitogen-activated protein kinase and mTOR-AKT pathways in some of these histiocytoses, our understanding of these diseases has now evolved from the concept of a primary inflammatory condition to that of a clonal neoplastic disease. This understanding has led to the development of effective mechanism-based therapeutic strategies for patients with histiocytic diseases.
authors.affiliation: Service de Médecine Interne 2, Centre National de Référence Maladies Auto Immunes Systémiques Rares, Institut E3M, Hôpital Pitié-Salpêtrière, Paris, France. Electronic address: julien.haroche@aphp.fr.
authors.forename: Julien
authors.initials: J
authors.lastname: Haroche
authors.affiliation: Service de Médecine Interne 2, Centre National de Référence Maladies Auto Immunes Systémiques Rares, Institut E3M, Hôpital Pitié-Salpêtrière, Paris, France.
authors.forename: Fleur
authors.initials: F
authors.lastname: Cohen-Aubart
authors.affiliation: Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
authors.forename: Barret J
authors.initials: BJ
authors.lastname: Rollins
authors.affiliation: AP-HP, Service d'Hématologie, Hôpital Trousseau, Paris, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Donadieu
authors.affiliation: AP-HP, Service d'Anatomocytopathologie, Hôpital Pitié-Salpêtrière, Paris, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Charlotte
authors.affiliation: AP-HP, Service de neurologie Mazarin, Hôpital Pitié-Salpêtrière, Paris, France.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Idbaih
authors.affiliation: Nephrology Unit, University Hospital, Parma, Italy.
authors.forename: Augusto
authors.initials: A
authors.lastname: Vaglio
authors.affiliation: Leukemia Service, Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Omar
authors.initials: O
authors.lastname: Abdel-Wahab
authors.affiliation: EA4340 and Pathology Department, Ambroise Paré Hospital AP-HP and Versailles University, Boulogne, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Emile
authors.affiliation: Service de Médecine Interne 2, Centre National de Référence Maladies Auto Immunes Systémiques Rares, Institut E3M, Hôpital Pitié-Salpêtrière, Paris, France.
authors.forename: Zahir
authors.initials: Z
authors.lastname: Amoura
mesh_terms: D000818:Animals; D006646:Histiocytosis, Langerhans-Cell / Q000175:diagnosis* / Q000209:etiology*; D006801:Humans; D007249:Inflammation / Q000150:complications*; D009369:Neoplasms / Q000175:diagnosis* / Q000209:etiology*