title: Pulmonary Langerhans cell histiocytosis: evolution of lesions on CT scans.
abstract: OBJECTIVE
  To document the evolution of pulmonary lesions of Langerhans cell histiocytosis (LCH) with sequential computed tomography (CT).
  
  
  METHODS
  Initial and final CT scans of 21 patients with LCH and CT evidence of pulmonary disease were compared retrospectively. Histologic confirmation of pulmonary involvement was available in 11 patients.
  
  
  RESULTS
  On initial CT images, a nodular pattern (n = 14) was seen more frequently than a cystic pattern (n = 7). On final CT images, a cystic pattern (n = 14) was seen more often than a nodular one (n = 6). There was complete resolution of parenchymal abnormality in one case. Nodular opacities, thick-walled cysts, and ground-glass opacities underwent regression. Thin-walled cysts, linear opacities, and emphysematous lesions remained unchanged or progressed.
  
  
  CONCLUSIONS
  Pulmonary CT allows good assessment of the evolution of LCH lesions. Nodular lesions probably represent active disease and often undergo regression or transform into cysts.
authors.affiliation: Department of Radiology, Université Paris XIII, Hópital Avicenne, Bobigny, France.
authors.forename: M W
authors.initials: MW
authors.lastname: Brauner
authors.forename: P
authors.initials: P
authors.lastname: Grenier
authors.forename: K
authors.initials: K
authors.lastname: Tijani
authors.forename: J P
authors.initials: JP
authors.lastname: Battesti
authors.forename: D
authors.initials: D
authors.lastname: Valeyre
mesh_terms: D000328:Adult; D004803:Eosinophilic Granuloma / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D017563:Lung Diseases, Interstitial / Q000000981:diagnostic imaging*; D008297:Male; D012189:Retrospective Studies; D013997:Time Factors; D014057:Tomography, X-Ray Computed