title: Comparative clinicopathology of obliterative bronchiolitis and diffuse panbronchiolitis.
abstract: BACKGROUND
  The progressive airway obliteration caused by obliterative bronchiolitis (OB) has been widely noted in the world. In contrast, the obstructive respiratory disorder caused by diffuse panbronchiolitis (DPB) has been reported mainly from Japan. Therefore, there might be a considerable overlap between OB and DPB in Japan.
  
  
  OBJECTIVE
  To clarify the clinicopathological similarities as well as the differences between OB and DPB, 15 patients with OB and 6 patients with DPB were evaluated clinicopathologically.
  
  
  RESULTS
  The underlying disorders in OB were graft-versus-host disease (GVHD) in 7, rheumatoid arthritis in 3, Kartagener's syndrome in 2, and polymyositis/dermatomyositis, non-tuberculous mycobacterial disease and mycoplasmal pneumonia in one each. The lung pathology demonstrated that the primary obstructive lesions were in the membranous bronchioli in OB. In contrast, they were confined to the respiratory bronchioli in DPB. In addition, OB was classified into two major morphologic types, namely, constrictive and cellular. Clinical manifestations included cough and/or dyspnea in 13 with OB and in 6 with DPB, chronic parasinusitis in 3 with cellular OB and in 6 with DPB. The pulmonary function tests revealed obstructive impairments in all patients with OB and DPB. The chest CT images showed small centrilobular nodules in 64% of those with OB and in all with DPB. The prognosis of constrictive OB was worse than that of cellular OB and DPB.
  
  
  CONCLUSIONS
  This study demonstrated that histopathologically marked differences existed between OB and DPB, although striking similarities in clinical manifestations were also noted in both diseases.
authors.affiliation: Department of Respiratory Medicine, Respiratory Center and Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan. sa-homma@toranomon.gr.jp
authors.forename: Sakae
authors.initials: S
authors.lastname: Homma
authors.forename: Susumu
authors.initials: S
authors.lastname: Sakamoto
authors.forename: Masateru
authors.initials: M
authors.lastname: Kawabata
authors.forename: Kazuma
authors.initials: K
authors.lastname: Kishi
authors.forename: Eiyasu
authors.initials: E
authors.lastname: Tsuboi
authors.forename: Noriko
authors.initials: N
authors.lastname: Motoi
authors.forename: Akira
authors.initials: A
authors.lastname: Hebisawa
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Yoshimura
mesh_terms: D000328:Adult; D001344:Autopsy; D001988:Bronchiolitis / Q000473:pathology* / Q000503:physiopathology; D001989:Bronchiolitis Obliterans / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests; D014397:Tuberculosis, Pulmonary / Q000473:pathology / Q000503:physiopathology