title: Labyrinthine involvement in Langerhans' cell histiocytosis.
abstract: BACKGROUND
  Langerhans' cell histiocytosis, a rare condition caused by the proliferation of abnormal Langerhans' cells ('LCH cells') and an accompanying granulomatous infiltrate, can affect several organs including the ear. External and middle ear involvement are common with a reported incidence as high as 61%. The bony labyrinth is resistant to erosion by the granulation tissue, thereby protecting the cochlea and vestibular structures. Probably for this reason, involvement of the inner ear is rare, with few case reports in the literature.
  
  
  METHODS
  We report two girls, one with bilateral and the other with unilateral mastoid involvement, in whom there was invasion of the labyrinth. The first girl had 'single system' LCH affecting only bone and developed an acute hearing loss due to invasion of the cochlea, while the second had both bone and skin involvement and labyrinthine involvement was diagnosed on imaging prior to the onset of labyrinthine symptoms.
  
  
  CONCLUSIONS
  Inner ear involvement can lead to permanent deafness, which may be prevented by early institution of treatment. Threatened inner ear involvement requires urgent systemic medical therapy with steroids, possibly combined with chemotherapy.
authors: Department of Haematology/Oncology, Great Ormond Street Hospital for Children, London, UK. V.Nanduri@ich.ucl.ac.uk
authors: V R
authors: VR
authors: Nanduri
authors: J
authors: J
authors: Pritchard
authors: W K
authors: WK
authors: Chong
authors: P D
authors: PD
authors: Phelps
authors: K
authors: K
authors: Sirimanna
authors: C M
authors: CM
authors: Bailey
mesh_terms: D002675:Child, Preschool; D003638:Deafness / Q000209:etiology; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000209:etiology; D006646:Histiocytosis, Langerhans-Cell / Q000150:complications* / Q000628:therapy; D006801:Humans; D007759:Labyrinth Diseases / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D008416:Mastoid / Q000473:pathology