title: Langerhans cell histiocytosis and juvenile xanthogranuloma. Two case reports.
abstract: BACKGROUND
  Histiocytoses represent a large, puzzling group of diseases which may involve the skin and other organs. At present, juvenile xanthogranuloma is the disorder most often confused with Langerhans cell histiocytosis. A complex overlap exists between juvenile xanthogranuloma and Langerhans cell histiocytosis, with lesions showing clinical and/or pathological features of both disorders.
  
  
  METHODS
  We report 2 patients affected by Langerhans cell histiocytosis who, during chemotherapy, presented cutaneous lesions with clinical and histological features of juvenile xanthogranuloma. During the therapy, in both cases, histological examination of new biopsies revealed the presence of Touton giant cells in the dermis with a few histiocytic cells; immunohistochemical staining was negative for CD1a, and no Birbeck granules were seen by ultrastructural examination.
  
  
  CONCLUSIONS
  A possible explanation for the link between Langerhans cell histiocytosis and juvenile xanthogranuloma regards the lineage development and the relationships of histiocytes. We suggest that chemotherapy can modify the production of cytokines by influencing the conversion or 'maturation' of pathological cells into macrophages or xanthomatous cells and fusing them to form multinucleated giant Touton cells. In our opinion, the modification of the cutaneous lesions during chemotherapy in Langerhans cell histiocytosis patients, as observed in our cases, could be a favorable prognostic factor.
authors.affiliation: Department of Clinical and Experimental Medicine, Division of Dermatology, University of Study of Bologna, Bologna, Italy. patrizi@almadns.unibo.it
authors.forename: Annalisa
authors.initials: A
authors.lastname: Patrizi
authors.forename: Iria
authors.initials: I
authors.lastname: Neri
authors.forename: Federica
authors.initials: F
authors.lastname: Bianchi
authors.forename: Valentina
authors.initials: V
authors.lastname: Guerrini
authors.forename: Cosimo
authors.initials: C
authors.lastname: Misciali
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Paone
authors.forename: Roberta
authors.initials: R
authors.lastname: Burnelli
mesh_terms: D000293:Adolescent; D003937:Diagnosis, Differential; D005260:Female; D006646:Histiocytosis, Langerhans-Cell / Q000150:complications / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D008297:Male; D014972:Xanthogranuloma, Juvenile / Q000150:complications / Q000175:diagnosis* / Q000473:pathology