The associations among radiological characteristics, growth, and pathological results of pulmonary subsolid nodules

The study aim was to retrospectively compare pulmonary subsolid nodules observed on Computed Tomography (CT) scans with findings on follow-up CT images after more than 2 y. The Institutional Review Board has approved this study. We retrospectively reviewed 203 subsolid nodules found in 169 patients. Findings on CT images were evaluated in terms of nodule size, development of a new internal solid component, and the type of relationship between the nodules and blood vessels. Nodules from 61 out of 169 patients were resected and pathological findings were recorded. The frequency of growth of subsolid nodules was 30.0% (61 out of 203 nodules). For nonsolid nodules, the frequency was 27.0% (51 of 189); for part-solid nodules, the frequency was 71.1% (10 of 14). Nodule growth was significantly associated with type of nodule (nonsolid or part-solid), initial size, development of a new solid portion, and type of relationship between nodules and blood vessels. The average volume doubling time was 873 d for nonsolid nodules and 793 d for part-solid nodules. Of the 189 nonsolid nodules, 67 were resected (19 invasive adenocarcinomas, 14 Minimally Invasive Adenocarcinomas (MIAs), 25 Adenocarcinomas In Situ (AIS), 6 Atypical Adenomatous Hyperplasia's (AAHs), and 3 benign conditions). Of the 14 part-solid nodules, 5 were resected (3 invasive adenocarcinomas and 2 AIS). During long-term follow-up, 30.0% of subsolid nodules had grown. Of the grown nodules that were resected, 26.5% were MIAs and 58.8% were invasive adenocarcinomas.