title: Familial idiopathic interstitial pneumonia: histopathology and survival in 30 patients.
abstract: BACKGROUND
  Familial idiopathic interstitial pneumonia (F-IIP) describes the unexplained occurrence of diffuse parenchymal lung disease in related individuals. Prevailing wisdom suggests that the histopathology of F-IIP is indistinguishable from that of idiopathic pulmonary fibrosis, namely, usual interstitial pneumonia (UIP).
  
  
  OBJECTIVE
  To define the histopathology of F-IIP in lung tissue samples.
  
  
  METHODS
  Tissue sections from 30 patients with F-IIP, enrolled in a national research program, were evaluated by 3 pulmonary pathologists using 15 predefined histopathologic features. Each feature was recorded independently before a final diagnosis was chosen from a limited list dichotomized between UIP or "not UIP." These 2 groups were then compared to survival.
  
  
  RESULTS
  The consensus diagnosis for the F-IIP cohort was an unclassifiable parenchymal fibrosis (60%), with a high incidence of histopathologic honeycombing, fibroblast foci, and smooth muscle in fibrosis. Usual interstitial pneumonia, strictly defined, was identified in less than half of the F-IIP cases (range, 23%-50%). Interobserver agreement was fair (κ  =  0.37) for 2 observers for the overall diagnosis of UIP. Findings unexpected in UIP were prevalent. The survival for the entire F-IIP cohort was poor, with an estimated mortality of 93% and a median age at death of 60.9 years. Subjects with UIP had a shorter survival and younger age at death.
  
  
  CONCLUSIONS
  Pulmonary fibrosis was the dominant histopathology identified in our patients, but diagnostic features of UIP were seen in less than 50% of the samples. Overall survival was poor, with mortality accelerated apparently by the presence of a UIP pattern of disease.
authors.affiliation: Department of Pathology, Mayo Clinic Arizona, 13400 East Shea Blvd, Scottsdale, AZ 85259, USA. Leslie.Kevin@mayo.edu
authors.forename: Kevin O
authors.initials: KO
authors.lastname: Leslie
authors.forename: Carlyne D
authors.initials: CD
authors.lastname: Cool
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Sporn
authors.forename: Douglas
authors.initials: D
authors.lastname: Curran-Everett
authors.forename: Mark P
authors.initials: MP
authors.lastname: Steele
authors.forename: Kevin K
authors.initials: KK
authors.lastname: Brown
authors.forename: Momen M
authors.initials: MM
authors.lastname: Wahidi
authors.forename: David A
authors.initials: DA
authors.lastname: Schwartz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000235:genetics* / Q000401:mortality / Q000473:pathology*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011379:Prognosis; D014481:United States / Q000453:epidemiology; D055815:Young Adult