title: Natural history of pure ground-glass opacity after long-term follow-up of more than 2 years.
abstract: BACKGROUND
  Pure ground-glass opacity (PGGO) is a new entity that has been clearly defined on high-resolution computed tomography (CT) during the last half decade. It is important to investigate the natural history of PGGO through long-term observation for the management of this new entity.
  
  
  METHODS
  We investigated 19 patients with PGGO(s) defined on high-resolution computed tomography and retained as PGGO for more than 2 years. The PGGOs of 11 patients were detected at annual mass screening by low-radiation-dose CT (low-dose CT), 7 at follow-up CT after cancer resection, and 1 incidentally on CT. After long-term observation, 10 of 19 patients underwent operation and 9 are currently being followed-up with CT. Their growth characteristics and histologic findings are reported.
  
  
  RESULTS
  The median follow-up period was 32 months, ranging from 24 to 124 months. The sizes of PGGOs at the time of discovery were 4 to 18 mm in largest diameter (average 8.6 mm). During follow-up, the size of PGGO showed no change in 8 patients, increased slightly (up to 5 mm) in 6 patients, and increased by more than 5 mm in 5 patients. Ten patients had limited resection (segmentectomy or wide wedge resection) with negative surgical margin by intraoperative lavage cytology of the resection margin of the lung. Of them, 5 patients had adenocarcinoma, 3 pulmonary lymphoproliferative disorder, and 1 each atypical adenomatous hyperplasia and focal fibrosis. There was no clear tendency between the degree of size change and histology. In all but 1 of 9 patients with follow-up only, the PGGOs showed either no change or only a slight increase within 5 mm in largest diameter.
  
  
  CONCLUSIONS
  These data suggest that some PGGOs will never progress to clinical disease and would be included in the category of overdiagnosis bias. However, a prior history of lung cancer should significantly raise the index of suspicion, as 4 of 5 proven cancer cases in this small series fell into that category. Because of the difficulties of preoperative and intraoperative histodiagnosis of PGGO, minimally invasive surgery may be appropriate from the viewpoints of both diagnosis and curability.
authors.affiliation: Department of Thoracic Surgery, Field Research and Internal Medicine, Osaka Medical Center for Cancer and Cardiovascular Diseases, Japan. kdm@ma2.justnet.ne.jp
authors.forename: Ken
authors.initials: K
authors.lastname: Kodama
authors.forename: Masahiko
authors.initials: M
authors.lastname: Higashiyama
authors.forename: Hideoki
authors.initials: H
authors.lastname: Yokouchi
authors.forename: Koji
authors.initials: K
authors.lastname: Takami
authors.forename: Keiko
authors.initials: K
authors.lastname: Kuriyama
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kusunoki
authors.forename: Tomio
authors.initials: T
authors.lastname: Nakayama
authors.forename: Fumio
authors.initials: F
authors.lastname: Imamura
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D000236:Adenoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006965:Hyperplasia / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D008171:Lung Diseases / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008232:Lymphoproliferative Disorders / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011013:Pneumonectomy; D011658:Pulmonary Fibrosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D011856:Radiographic Image Enhancement; D020775:Thoracic Surgery, Video-Assisted; D014057:Tomography, X-Ray Computed