title: Histiocytosis: a review focusing on neuroimaging findings.
abstract: OBJECTIVE
  Histiocytosis is a systemic disease that usually affects the central nervous system. The aim of this study is to discuss the neuroimaging characteristics of Langerhans cell histiocytosis (LCH), the most common of these diseases; and the non-Langerhans cells histiocytosis (NLCH), which includes entities such as hemophagocytic syndrome, Erdheim-Chester and Rosai-Dorfman diseases.
  
  
  METHODS
  Literature review and illustrative cases with pathologic confirmation.
  
  
  RESULTS
  In LCH, the most common findings are 1) osseous lesions in the craniofacial bones and/or skull base; 2) intracranial, extra-axial changes; 3) intra-axial parenchymal changes (white and gray matter); 4) atrophy. Among the NLCH, diagnosis usually requires correlation with clinical and laboratory criteria. The spectrum of presentation includes intraparenchymal involvement, meningeal lesions, orbits and paranasal sinus involvement.
  
  
  CONCLUSIONS
  It is important the recognition of the most common imaging patterns, in order to include LCH and NLCH in the differential diagnosis, whenever pertinent.
authors: Instituto de Radiologia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, Sao Paulo, SP, Brazil.
authors: Larissa Barcessat
authors: LB
authors: Gabbay
authors: Departamento de Radiologia, Faculdade de Medicina, Universidade de São Paulo, Sao Paulo, SP, Brazil.
authors: Cláudia da Costa
authors: Cda C
authors: Leite
authors: Instituto de Radiologia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, Sao Paulo, SP, Brazil.
authors: Ranieli Saraiva
authors: RS
authors: Andriola
authors: Instituto de Radiologia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, Sao Paulo, SP, Brazil.
authors: Paula da Cunha
authors: Pda C
authors: Pinho
authors: Centro de Diagnósticos Brasil (CDB), Sao Paulo, SP, Brazil.
authors: Leandro Tavares
authors: LT
authors: Lucato
mesh_terms: D003937:Diagnosis, Differential; D005260:Female; D006646:Histiocytosis, Langerhans-Cell / Q000473:pathology*; D015616:Histiocytosis, Non-Langerhans-Cell / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D059906:Neuroimaging / Q000379:methods*