title: Concurrent Langerhans cell histiocytosis and myelodysplasia in children.
abstract: BACKGROUND
  Langerhans cell histiocytosis (LCH) is characterized by the proliferation of abnormal histiocytes (Langerhans cells), whose origin as a reactive process or a neoplastic disorder is still poorly understood. Although LCH has been recorded as being associated with malignant neoplasms, concurrence of LCH and myelodysplastic syndrome has not been reported so far.
  
  
  METHODS
  We report on four children aged 23, 25, 26, and 53 months with multisystem LCH with organ dysfunction (bone marrow and liver) whose bone marrow pictures, taken at diagnosis, revealed the presence of myelodysplastic abnormalities (RA, RAEB, RAEB-t).
  
  
  RESULTS
  We suggest that the commonly used expression of "organ dysfunction," which refers to clinical and functional alterations, could be explained by a myelodysplastic-like disorder.
  
  
  CONCLUSIONS
  The contemporary presence of both events may provide a better understanding of the pathogenesis of LCH, especially in young children with multisystem disease and organ dysfunction, who are known to have a very poor outcome.
authors.affiliation: Department of Pediatric Hematology and Oncology, II Pediatric Clinic, University of Bari, Bari, Italy. n.rigillo@pediatria2.uniba.it
authors.forename: G
authors.initials: G
authors.lastname: Surico
authors.forename: P
authors.initials: P
authors.lastname: Muggeo
authors.forename: N
authors.initials: N
authors.lastname: Rigillo
authors.forename: H
authors.initials: H
authors.lastname: Gadner
mesh_terms: D001854:Bone Marrow Cells / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006646:Histiocytosis, Langerhans-Cell / Q000150:complications* / Q000175:diagnosis*; D006801:Humans; D007223:Infant; D008297:Male; D009190:Myelodysplastic Syndromes / Q000150:complications* / Q000175:diagnosis