title: Utility of bronchoscopy in pulmonary Langerhans cell histiocytosis.
abstract: BACKGROUND
  Pulmonary Langerhans cell histiocytosis (PLCH) is an uncommon form of interstitial lung disease and is usually smoking-related when seen in adults. There are relatively little data regarding the utility of bronchoscopic lung biopsy for this disorder.
  
  
  METHODS
  A computer-assisted search was carried out to identify patients with PLCH seen at Mayo Clinic Rochester, MN from 1997 to 2012 and who underwent bronchoscopy with lung biopsy. Approval was obtained from the Mayo Foundation Institutional Review Board before beginning the study. Medical records of these patients were reviewed to extract data with regard to demographic and clinical features, imaging studies, and biopsy results.
  
  
  RESULTS
  Thirty-eight patients with PLCH underwent diagnostic bronchoscopy with biopsies. Their median age was 39.5 years (range, 21 to 66 y) and included 24 women. Thirty-two patients (84%) were current smokers at the time of the diagnosis, 5 were ex-smokers (13%), and 1 was a never-smoker (3%). The diagnosis of PLCH required the presence of typical histopathologic features on surgical or bronchoscopic lung biopsy, >5% CD1a-positive cells in the bronchoalveolar lavage (BAL), and/or biopsy of an extrapulmonary site in the presence of clinical and chest computed tomographic findings compatible with the diagnosis. Bronchoscopic biopsy yielded diagnostic specimens that allowed the diagnosis of PLCH in 19 patients (50%). CD1a immunostaining of BAL cells had been performed in 8 patients and demonstrated ≥ 5% CD1a-positive BAL cells in 3 additional patients (8%).
  
  
  CONCLUSIONS
  We conclude that bronchoscopic lung biopsy is useful in the diagnosis of PLCH and should be the initial method of obtaining diagnostic specimens.
authors.affiliation: Divisions of *Pulmonary and Critical Care Medicine †Anatomic Pathology, Mayo Clinic, Rochester, MN.
authors.forename: Misbah
authors.initials: M
authors.lastname: Baqir
authors.forename: Robert
authors.initials: R
authors.lastname: Vassallo
authors.forename: Fabien
authors.initials: F
authors.lastname: Maldonado
authors.forename: Eunhee S
authors.initials: ES
authors.lastname: Yi
authors.forename: Jay H
authors.initials: JH
authors.lastname: Ryu
mesh_terms: D000328:Adult; D000368:Aged; D018949:Antigens, CD1 / Q000378:metabolism; D001706:Biopsy; D018893:Bronchoalveolar Lavage / Q000379:methods*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D001999:Bronchoscopy / Q000379:methods*; D005260:Female; D006646:Histiocytosis, Langerhans-Cell / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D013194:Staining and Labeling; D055815:Young Adult
chemical_list: D018949:Antigens, CD1