title: Respiratory bronchiolitis and lung carcinoma.
abstract: BACKGROUND
  Cigarette smoking is the primary causative factor for lung carcinoma and respiratory bronchiolitis (RB), particularly RB-associated interstitial lung disease (RB-ILD). However, the link between lung cancer and RB/RB-ILD remains undefined. We examined whether pathological fibrosis lesions exist simultaneously in patients with lung carcinoma because the fibrous lesions could be precancerous.
  
  
  METHODS
  Clinical, radiological, and pathological features were consecutively evaluated in 67 current smokers, 22 ex-smokers, and 35 nonsmokers who underwent surgical resection for lung carcinoma. The presence of interstitial changes was evaluated by high-resolution computed tomography (HRCT). The pathological examination focused on RB, RB with fibrosis, and coexistent interstitial changes.
  
  
  RESULTS
  RB with fibrosis was observed in 13/67 current smokers with centrilobular nodular and/or patchy ground-glass opacities patterns or emphysema on HRCT. RB without fibrosis was observed in 12/67 current smokers with a centrilobular pattern, emphysema, or a normal pattern on HRCT. The Brinkman smoking index was significantly higher in the RB with fibrosis group (1278±133) than in the RB without fibrosis group (791±131). No RB with/without fibrosis features were noted in nonsmokers or ex-smokers. Squamous cell carcinoma was observed in 11/13 patients with RB with fibrosis, whereas adenocarcinoma was observed in 7/12 patients with RB without fibrosis.
  
  
  CONCLUSIONS
  Squamous cell carcinoma located in peripheral areas was primarily observed in patients with RB with fibrosis, whereas adenocarcinoma was primarily observed in patients with RB without fibrosis. Interstitial fibrosis with RB caused by continuous heavy cigarette smoking may increase the risk of developing squamous cell carcinoma.
authors: Department of Chest Medicine, Japan Railway Tokyo General Hospital, Japan.
authors: Yoshihito
authors: Y
authors: Yamada
authors: Jiro
authors: J
authors: Terada
authors: Koichiro
authors: K
authors: Tatsumi
authors: Chiyoko
authors: C
authors: Kono
authors: Masataka
authors: M
authors: Tanno
authors: Tamiko
authors: T
authors: Takemura
authors: Tetsuo
authors: T
authors: Yamaguchi
mesh_terms: D000368:Aged; D001988:Bronchiolitis / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D017563:Lung Diseases, Interstitial / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011658:Pulmonary Fibrosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology; D013902:Radiography, Thoracic; D012306:Risk; D012907:Smoking / Q000009:adverse effects*; D014057:Tomography, X-Ray Computed
keywords: Bronchiolocentric fibrosis; Respiratory bronchiolitis; Smoking; Smoking-related interstitial fibrosis; Squamous cell carcinoma