title: Organizing pneumonia components in non-specific interstitial pneumonia (NSIP): a clinicopathological study of 33 NSIP cases.
abstract: OBJECTIVE
  To review the clinical, radiological and pathological features of non-specific interstitial pneumonia (NSIP), mainly to characterize organizing pneumonia (OP) components in NSIP.
  
  
  RESULTS
  Lung biopsy samples from 33 NSIP patients were collected over a period of 10 years. Microscopic analysis revealed that 13 cases showed a cellular pattern and 20 showed a mixed/fibrosing pattern. OP components were detected in 26 cases (13 with a cellular pattern; 13 with a mixed/fibrosing pattern), and were found to constitute a median proportion of 9% (range, 1-40%) of the affected tissues. In nine cellular and four mixed/fibrosing NSIP cases, the OP components accounted for ≥10%. A proportion of ≥20% was found in only five cellular pattern cases. Twenty-nine patients were followed up: 17 showed improvements, five were stabilized, and seven showed progression.
  
  
  CONCLUSIONS
  OP components are common basic lesions in NSIP cases, although their proportion in cellular and mixed/fibrosing pattern cases varies substantially between patients. OP components do not impact on prognosis, even when they constitute ≥20% of the affected tissue. Thus, a high level of OP components does not exclude a diagnosis of NSIP in cases that otherwise show pathological and radiological findings characteristic of NSIP.
authors.affiliation: Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Huo
authors.affiliation: Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors.forename: Ji
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Thoracic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors.forename: Shanqing
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors.forename: Haibo
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors.forename: Zhengyu
authors.initials: Z
authors.lastname: Jin
authors.affiliation: Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors.forename: Junyi
authors.initials: J
authors.lastname: Pang
authors.affiliation: Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors.forename: Hongrui
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Respiratory Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors.forename: Juhong
authors.initials: J
authors.lastname: Shi
authors.affiliation: Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors.forename: Ruie
authors.initials: R
authors.lastname: Feng
mesh_terms: D000328:Adult; D000368:Aged; D018549:Cryptogenic Organizing Pneumonia / Q000473:pathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008168:Lung / Q000473:pathology; D017563:Lung Diseases, Interstitial / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011658:Pulmonary Fibrosis / Q000473:pathology*; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: high-resolution computed tomography scan; lung biopsy; non-specific interstitial pneumonia; organizing pneumonia components; pathology