title: Pathologic and radiologic differences between idiopathic and collagen vascular disease-related usual interstitial pneumonia.
abstract: BACKGROUND
  Patients with usual interstitial pneumonia (UIP) associated with collagen vascular disease (CVD) have been reported to have a better prognosis than those with idiopathic pulmonary fibrosis with a UIP pattern (IPF/UIP) seen on histology. The aim of this study was to evaluate the pathologic and radiologic differences between the two conditions and their relationship with clinical outcome.
  
  
  METHODS
  A retrospective review of 100 patients (CVD-UIP, 39 patients; IPF/UIP, 61 patients) with UIP pattern diagnosed by surgical lung biopsy at one tertiary referral center.
  
  
  RESULTS
  The median follow-up period was 34.4 months. The CVD-UIP group was younger, included more women and nonsmokers, and showed better survival than the IPF/UIP group. Pathologically, CVD-UIP patients had fewer fibroblastic foci and smaller honeycombing (HC) spaces with higher germinal centers and total inflammation scores than IPF/UIP patients. Radiologically, CVD-UIP patients had a lower emphysema score and more likely a nontypical UIP pattern without HC. The germinal centers score was the best distinguishing feature between CVD-UIP and IPF/UIP patients (odds ratio, 2.948; p = 0.001) and was marginally related to survival (p = 0.076). The HC score (hazard ratio [HR], 1.134; p < 0.001), total lung capacity (TLC) [HR, 0.932; p = 0.004], and age (HR, 1.052; p = 0.017) were significant predictors of survival in all patients with UIP histology, regardless of the presence of CVD. Among IPF/UIP patients, those with positive autoantibodies were pathologically more similar to CVD-UIP than to IPF/UIP without autoantibodies, despite no difference in survival between them.
  
  
  CONCLUSIONS
  The germinal centers score was the best discriminative between CVD-UIP and IPF/UIP patients; it was of marginal prognostic significance. Age, TLC, and HC score were independent prognostic factors in all patients with UIP histology.
authors.affiliation: Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Jin Woo
authors.initials: JW
authors.lastname: Song
authors.affiliation: Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Kyung-Hyun
authors.initials: KH
authors.lastname: Do
authors.affiliation: Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea. Electronic address: dskim@amc.seoul.kr.
authors.forename: Mi-Young
authors.initials: MY
authors.lastname: Kim
authors.affiliation: Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Se Jin
authors.initials: SJ
authors.lastname: Jang
authors.affiliation: Department of Pathology, Mayo Clinic, Rochester, MN.
authors.forename: Thomas V
authors.initials: TV
authors.lastname: Colby
authors.affiliation: Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
authors.forename: Dong Soon
authors.initials: DS
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003095:Collagen Diseases / Q000150:complications* / Q000175:diagnosis / Q000401:mortality; D005260:Female; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed; D014652:Vascular Diseases / Q000150:complications* / Q000175:diagnosis / Q000401:mortality