title: Evolution of peripheral lung adenocarcinomas: CT findings correlated with histology and tumor doubling time.
abstract: OBJECTIVE
  This study was performed to evaluate the evolution of peripheral lung adenocarcinomas using CT findings and histologic classification related to tumor doubling time.
  
  
  METHODS
  The subjects were 34 patients, each with an adenocarcinoma smaller than 3 cm. All patients underwent chest radiography and 10 of them had previously undergone CT more than 6 months before surgery. Tumor doubling time was estimated by examining sequential radiographs using the method originally described by Schwartz. Tumor growth was also observed by studying the changes on CT in the 10 patients who had previously undergone CT. The histologic classification (types A-F) was evaluated according to the criteria of Noguchi et al.
  
  
  RESULTS
  Five (83%) of the six adenocarcinomas with tumor types A or B showed localized ground-glass opacity on high-resolution CT. All six tumors had a tumor doubling time of more than 1 year. Fifteen (71%) of the 21 tumors with type C showed partial ground-glass opacity mixed with localized solid attenuation on high-resolution CT. Ten (48%) of these 21 type C tumors had a tumor doubling time of more than 1 year. In types B and C, the solid component or the development of pleural indentation and vascular convergence increased during observation before surgery. All seven tumors with types D, E, and F showed mostly solid attenuation, and the tumor doubling time was less than 1 year in six (87%) of the seven tumors.
  
  
  CONCLUSIONS
  Two main types of peripheral lung adenocarcinoma exist. The first type appears on CT as a localized ground-glass opacity with slow growth, and the other appears as a solid attenuation with rapid growth.
authors.affiliation: Department of Radiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu-shi, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Aoki
authors.forename: H
authors.initials: H
authors.lastname: Nakata
authors.forename: H
authors.initials: H
authors.lastname: Watanabe
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: T
authors.initials: T
authors.lastname: Kasai
authors.forename: H
authors.initials: H
authors.lastname: Hashimoto
authors.forename: K
authors.initials: K
authors.lastname: Yasumoto
authors.forename: M
authors.initials: M
authors.lastname: Kido
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology; D000368:Aged; D000369:Aged, 80 and over; D002455:Cell Division / Q000502:physiology*; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011379:Prognosis; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed