title: Pulmonary sarcoidosis mimicking cryptogenic fibrosing alveolitis on CT.
abstract: OBJECTIVE
  The high resolution CT (HRCT) characteristics of fibrosing alveolitis and sarcoidosis are well established, and HRCT has been shown to have a high diagnostic accuracy in these two conditions. We report two cases of sarcoidosis with features in common with the usual appearances of cryptogenic fibrosing alveolitis (CFA).
  
  
  METHODS
  Two adult male patients with sarcoidosis established by transbronchial biopsy or open lung biopsy who had undergone HRCT scanning were reviewed. At presentation both cases had an atypical pattern of radiological abnormality more in keeping with the features of CFA. Two observers independently assessed the CT scans for accepted features of CFA and sarcoidosis.
  
  
  RESULTS
  In both cases CFA was the most likely radiological diagnosis based on the accepted HRCT criteria for this condition. In neither patient were the appearances suggestive of sarcoidosis. In both cases the predominant distribution of abnormality was peripheral, subpleural and in the lower lung zones rather than peribronchial, central and in the mid and upper lung zones. Nodular opacities were not present in either case.
  
  
  CONCLUSIONS
  HRCT is an accurate and reliable method of suggesting or confirming the diagnosis of CFA and sarcoidosis. In a very small number of cases, sarcoidosis may produce HRCT appearances almost identical to CFA.
authors.affiliation: Department of Radiology, Royal Brompton Hospital, London, UK.
authors.forename: S P
authors.initials: SP
authors.lastname: Padley
authors.forename: A R
authors.initials: AR
authors.lastname: Padhani
authors.forename: A
authors.initials: A
authors.lastname: Nicholson
authors.forename: D M
authors.initials: DM
authors.lastname: Hansell
mesh_terms: D000368:Aged; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D008875:Middle Aged; D011658:Pulmonary Fibrosis / Q000000981:diagnostic imaging*; D017565:Sarcoidosis, Pulmonary / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed