title: How many adenocarcinoma lung cancers come from bronchioloalveolar carcinoma?
abstract: There is emerging evidence that bronchioloalveolar carcinoma (BAC) is the forerunner of peripheral adenocarcinoma lung cancers (ALC). Since advanced stage ALC is often diagnosed on cytology alone, we hypothesized that the incidence of BAC is underreported and that a large proportion of ALC in our population are part of the BAC-adenocarcinoma sequence.
  
  
  
  We reviewed the pretreatment computed tomographic (CT) scans of 69 patients with ALC and looked for characteristic features of BAC.
  
  
  
  The median patient age was 63, and the majority were of Chinese descent (75.4%). Women comprised 43.5% of the patients (30 patients) and never-smokers comprised 47.8% (33 patients). Only 15 patients (21.7%) had surgical specimens. The presence of BAC components was reported in the pathology of 16 patients (23.2%). CT features classically associated with BAC were found in 35 patients (50.7%). These included air bronchograms or bubble-like lucencies in 24 patients (34.8%), ground-glass opacities in 19 (27.5%), consolidation or pneumonic picture in 11 (15.9%), diffuse small or miliary nodules in 10 (14.5%), and the CT angiogram sign in 4 (5.8%).
  
  
  
  We found provocative radiologic evidence that a large proportion of our ALC cases arise from BAC. The CT findings are consistent with current understanding of the likely pathogenesis of peripheral ALC.
authors.affiliation: Department of Hematology-Oncology, National University Hospital, National University Health System, Singapore Department of Diagnostic Imaging, National University Hospital, National University Health System, Singapore Cancer Science Institute of Singapore, National University of Singapore, Singapore Department of Pathology, National University Hospital, National University Health System, Singapore.
authors.forename: Alvin S
authors.initials: AS
authors.lastname: Wong
authors.affiliation: Department of Hematology-Oncology, National University Hospital, National University Health System, Singapore Department of Diagnostic Imaging, National University Hospital, National University Health System, Singapore Cancer Science Institute of Singapore, National University of Singapore, Singapore Department of Pathology, National University Hospital, National University Health System, Singapore.
authors.forename: Kar-Yin
authors.initials: KY
authors.lastname: Seto
authors.affiliation: Department of Hematology-Oncology, National University Hospital, National University Health System, Singapore Department of Diagnostic Imaging, National University Hospital, National University Health System, Singapore Cancer Science Institute of Singapore, National University of Singapore, Singapore Department of Pathology, National University Hospital, National University Health System, Singapore.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Ang
authors.affiliation: Department of Hematology-Oncology, National University Hospital, National University Health System, Singapore Department of Diagnostic Imaging, National University Hospital, National University Health System, Singapore Cancer Science Institute of Singapore, National University of Singapore, Singapore Department of Pathology, National University Hospital, National University Health System, Singapore.
authors.forename: Eunice
authors.initials: E
authors.lastname: Wong
authors.affiliation: Department of Hematology-Oncology, National University Hospital, National University Health System, Singapore Department of Diagnostic Imaging, National University Hospital, National University Health System, Singapore Cancer Science Institute of Singapore, National University of Singapore, Singapore Department of Pathology, National University Hospital, National University Health System, Singapore.
authors.forename: Tan-Min
authors.initials: TM
authors.lastname: Chin
authors.affiliation: Department of Hematology-Oncology, National University Hospital, National University Health System, Singapore Department of Diagnostic Imaging, National University Hospital, National University Health System, Singapore Cancer Science Institute of Singapore, National University of Singapore, Singapore Department of Pathology, National University Hospital, National University Health System, Singapore.
authors.forename: Min-En
authors.initials: ME
authors.lastname: Nga
authors.affiliation: Department of Hematology-Oncology, National University Hospital, National University Health System, Singapore Department of Diagnostic Imaging, National University Hospital, National University Health System, Singapore Cancer Science Institute of Singapore, National University of Singapore, Singapore Department of Pathology, National University Hospital, National University Health System, Singapore.
authors.forename: Ross A
authors.initials: RA
authors.lastname: Soo
keywords: Adenocarcinoma; bronchioloalveolar carcinoma; computed tomography; lung cancer; radiology