Radiological features of invasive adenocarcinoma presenting as pure ground-glass nodules

Objective To investigate the radiological features of invasive adenocarcinoma presenting as pGGN. Methods The pathological, clinical and imaging data of 45 pGGN lesions in 40 patients (9 males, 31 females; average age (56.31±3.44) years) with pulmonary adenocarcinoma in Tumor Hospital Affiliated to Harbin Medical University from November 2010 to April 2016 were analyzed retrospectively. All patients were confirmed by pathological diagnosis. χ2 test and two-sample t test were used. ROC curve analysis was also used to evaluate the optimal cut-off points of lesion size and mass for diagnosing invasive adenocarcinoma. Results There were 20 patients with adenocarcinoma of situ (AIS) and minimally invasive adenocarcinoma (MIA) in group 1 (23 pGGN lesions), while another 20 patients with invasive adenocarcinoma in group 2 (22 pGGN lesions). The vascular convergence sign between 2 groups was statistically significant (13/23 in group 1 and 19/22 in group 2; χ2=4.874, P<0.05). Statistically differences in the lesion size ((13.83±4.49) mm in group 1 and (20.32±5.97) mm in group 2) and in the lesion mass ((0.36±0.34) g in group 1 and (0.98±0.44) g in group 2) were found between 2 groups (t values: 4.131, 5.355; both P<0.01). ROC curve analysis showed that the optimal cut-off points of the size and the mass were 17.3 mm and 0.69 g respectively, with the sensitivities of 73%(16/22) and 77%(17/22), and the specificities of 87%(20/23) and 91%(21/23). Conclusion The size, mass, and vascular convergence sign are helpful to detect invasive adenocarcinoma present as pGGN. Key words: Lung neoplasms; Adenocarcinoma; Positron-emission tomography; Tomography, X-ray computed; Deoxyglucose