title: An unusual co-occurrence of Langerhans cell histiocytosis and Rosai-Dorfman disease: report of a case and review of the literature.
abstract: BACKGROUND
  The co-occurrence of Langerhans cell histiocytosis (LCH; disorder characterized by proliferation of Langerhans cells) and Rosai-Dorfman disease (RDD; histiocytic entity that is one of the non-Langerhans cell diseases) is extremely rare and raises several questions regarding the nature of the diseases.
  
  
  METHODS
  We describe a 10-year-old boy who presented with a 3-month history of right scalp swelling. Clinical, pathological, and imaging evaluation disclosed multiple LCH of bone and cutaneous RDD.
  
  
  RESULTS
  After initiating prednisone and vinblastine therapy, the patient developed an asymptomatic diffuse papular eruption. Biopsy revealed cutaneous RDD. Treatment was continued with a good response of bone LCH and significant amelioration of the cutaneous findings.
  
  
  CONCLUSIONS
  Co-occurrence of LCH and RDD is a rare phenomenon. Various explanations, including the role of chemotherapy, are suggested based on our and several previously reported cases.
authors: Department of Dermatology, Haemek Medical Center, Afula, Israel.
authors: Eran
authors: E
authors: Cohen-Barak
authors: Dganit
authors: D
authors: Rozenman
authors: Jan
authors: J
authors: Schafer
authors: Judith
authors: J
authors: Krausz
authors: Roni
authors: R
authors: Dodiuk-Gad
authors: Hertzel
authors: H
authors: Gabriel
authors: Ayelet
authors: A
authors: Shani-Adir
mesh_terms: D002648:Child; D006646:Histiocytosis, Langerhans-Cell / Q000150:complications* / Q000175:diagnosis / Q000628:therapy; D015618:Histiocytosis, Sinus / Q000150:complications* / Q000175:diagnosis / Q000628:therapy; D006801:Humans; D008297:Male