Discriminating between bronchiolar adenoma, adenocarcinoma in situ and minimally invasive adenocarcinoma of the lung with CT.

Abstract Purpose To identify computed tomography (CT) features that may help distinguish bronchiolar adenoma (BA) from lung adenocarcinomas in situ (AIS) and minimally invasive adenocarcinomas (MIA) among lung lesions presenting as ground-glass nodules (GGNs). Materials and methods A total of 140 patients with GGNs confirmed by surgery and pathology, were reviewed retrospectively. There were 68 men and 72 women with a mean age of 64.3 ± 8.9 (SD) years (range: 31 – 85 years). The CT features of BA, AIS, and MIA were analyzed and compared. CT features, including percentage of solid component, maximum diameter of solid component, lesion density, location, margin, shape, pseudo-cavitation, calcification, ill-defined peripheral opacity, and air bronchogram, were analyzed using multivariate logistic regression and receiver operating characteristic curves. Results There were 11/140 (7.9%) patients with BA (mean age, 67.7 ± 7.5 [SD]; range 45 – 77 years), 63/140 (45.0%) patients with AIS (mean age, 62.5 ± 8.6 [SD]; range 36 – 69 years) and 66/140 (47.1%) patients with MIA (mean age, 63.5 ± 7.9 [SD]; range 35 – 72 years). By comparison with AIS and MIA, significantly different CT features of BA included tumor size, solid component diameters, low CT attenuation of the ground-glass component, irregular shape, ill-defined peripheral opacity, pseudo-cavitation, and abnormal pulmonary vein. Ill-defined peripheral opacity (odds ratio, 1.060; 95% confidence interval [CI]: 1.020 – 1.380) and pseudo-cavitation (odds ratio, 1.236; 95% CI: 1.070 – 1.565) were variables independently associated with the diagnosis of BA. Conclusion CT provides morphological features that allow differentiating between BA and AIS-MIA among lung lesions presenting as GGNs.