title: Interstitial pneumonia related to undifferentiated connective tissue disease: pathologic pattern and prognosis.
abstract: BACKGROUND
  Undifferentiated connective tissue disease (UCTD) involves conditions characterized by both having symptoms of connective tissue disease (CTD) and autoantibodies but not fulfilling the criteria of a specific CTD. The frequency or prognosis of the usual interstitial pneumonia (UIP) pattern in UCTD is unknown, which may be confused with idiopathic pulmonary fibrosis (IPF). This study aimed to investigate the frequency of the UIP pattern in interstitial pneumonia related to UCTD and compare its prognosis with that of IPF and UCTD-nonspecific interstitial pneumonia (UCTD-NSIP).
  
  
  METHODS
  The medical records of 788 patients presumptively diagnosed with idiopathic interstitial pneumonia at Asan Medical Center from January 2005 to December 2012 were retrospectively reviewed. UCTD was diagnosed according to the criteria by Corte and colleagues, and the prognoses were compared between UCTD-UIP and UCTD-NSIP and between UCTD-UIP and IPF.
  
  
  RESULTS
  Among 105 patients with UCTD (13.3% of total subjects), 44 had a UIP pattern (by surgical lung biopsy: 24; by high-resolution CT scan: 20), 29 had a nonspecific interstitial pneumonia pattern (by surgical lung biopsy), and nine had an organizing pneumonia pattern (by biopsy). The overall survival of the UCTD-UIP group was shorter than that of the UCTD-NSIP group (P = .021) but significantly better than that of the IPF group (P = .042).
  
  
  CONCLUSIONS
  A UIP pattern, which seems to be frequent in UCTD, showed a poorer prognosis than that of UCTD-NSIP. However, the prognosis of UCTD-UIP was significantly better than that of IPF, highlighting the importance of searching for underlying UCTD in suspected IPF cases.
authors.affiliation: Department of Pulmonary and Critical Care Medicine; Asan Medical Center, College of Medicine, University of Ulsan, Seoul, South Korea.
authors.forename: Ho-Cheol
authors.initials: HC
authors.lastname: Kim
authors.affiliation: Department of Pulmonary and Critical Care Medicine; Asan Medical Center, College of Medicine, University of Ulsan, Seoul, South Korea.
authors.forename: Wonjun
authors.initials: W
authors.lastname: Ji
authors.affiliation: Department of Radiology; Asan Medical Center, College of Medicine, University of Ulsan, Seoul, South Korea.
authors.forename: Mi Young
authors.initials: MY
authors.lastname: Kim
authors.affiliation: Asan Medical Center, College of Medicine, University of Ulsan, Seoul, South Korea; Department of Laboratory Medicine and Pathology; Asan Medical Center, College of Medicine, University of Ulsan, Seoul, South Korea.
authors.forename: Thomas V
authors.initials: TV
authors.lastname: Colby
authors.affiliation: Mayo Clinic, Scottsdale, AZ; Department of Pathology; Asan Medical Center, College of Medicine, University of Ulsan, Seoul, South Korea.
authors.forename: Se Jin
authors.initials: SJ
authors.lastname: Jang
authors.affiliation: Division of Rheumatology, Department of Internal Medicine; Asan Medical Center, College of Medicine, University of Ulsan, Seoul, South Korea.
authors.forename: Chang-Keun
authors.initials: CK
authors.lastname: Lee
authors.affiliation: Department of Clinical Epidemiology and Biostatistics; Asan Medical Center, College of Medicine, University of Ulsan, Seoul, South Korea.
authors.forename: Seung Bong
authors.initials: SB
authors.lastname: Han
authors.affiliation: Department of Pulmonary and Critical Care Medicine; Asan Medical Center, College of Medicine, University of Ulsan, Seoul, South Korea. Electronic address: dskim615@gmail.com.
authors.forename: Dong Soon
authors.initials: DS
authors.lastname: Kim
mesh_terms: D000368:Aged; D001706:Biopsy; D003240:Connective Tissue Diseases / Q000150:complications* / Q000175:diagnosis; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology*; D017563:Lung Diseases, Interstitial / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed