title: Prognostic relevance of histological variants in nonspecific interstitial pneumonia.
abstract: OBJECTIVE
  Although histological non-specific interstitial pneumonia (NSIP) is concisely defined, overlap with other patterns is described. While most frequently idiopathic, NSIP is seen in various clinical contexts such as connective tissue diseases (CTDs) and chronic hypersensitivity pneumonitis (cHP). This study was designed to determine if NSIP could be separated into subgroups based on minor histological features and to correlate these subgroups with clinical associations and survival.
  
  
  RESULTS
  One hundred and thirty-six patients with biopsy-proven NSIP were included [clinical diagnosis: CTDs (23%), cHP (12%), idiopathic (65%)]. In addition to the agreed NSIP criteria, seven subgroups were identified: essential NSIP and six overlap subgroups according to superimposed minor histological features. Interobserver concordance resulted in the following consensus: essential NSIP (36%), usual interstitial pneumonia (UIP) overlap (26%), cHP overlap (10%), organizing pneumonia (OP) overlap (6%), organizing diffuse alveolar damage (DAD) overlap (10%), desquamative interstitial pneumonia overlap (7%) and lymphoid interstitial pneumonia overlap (2%). OP overlap was associated with CTDs (P = 0.04) and cHP overlap with a cHP clinical diagnosis (P = 0.02). Survival was different between subgroups (P = 0.0002). Organizing DAD overlap exhibited poorer survival at 5 years (32%), followed by UIP overlap (57%). Independent predictors of mortality were organizing DAD overlap (HR = 4.99, 95% CI = 2.15-11.58, P = 0.0002), UIP overlap (HR = 2.11, 95% CI = 1.12-3.99, P = 0.02) and a clinical diagnosis of cHP (HR = 2.17, 95% CI = 1.05-4.47, P = 0.035).
  
  
  CONCLUSIONS
  Non-specific interstitial pneumonia subdivision into pathological subgroups is clinically relevant from a prognostic and causal perspective.
authors.affiliation: Service d'Anatomie Pathologique, AP-HP, Hôpital Avicenne, Bobigny, France.
authors.forename: Marianne
authors.initials: M
authors.lastname: Kambouchner
authors.forename: Pierre
authors.initials: P
authors.lastname: Levy
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Nicholson
authors.forename: Kirsten
authors.initials: K
authors.lastname: Schubel
authors.forename: Eline
authors.initials: E
authors.lastname: Magois
authors.forename: Séverine
authors.initials: S
authors.lastname: Feuillet
authors.forename: Dominique
authors.initials: D
authors.lastname: Valeyre
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Bernaudin
authors.forename: Hilario
authors.initials: H
authors.lastname: Nunes
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007249:Inflammation / Q000473:pathology; D017563:Lung Diseases, Interstitial / Q000145:classification* / Q000401:mortality / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011650:Pulmonary Alveoli / Q000473:pathology; D011658:Pulmonary Fibrosis / Q000473:pathology
keywords: aetiology; non-specific interstitial pneumonia; pathology; survival