Background:

The preoperative differential diagnosis of nodular lung adenocarcinoma has long been a challenging issue for thoracic surgeons. This study aimed to explore differential diagnosis of nodular lung adenocarcinoma by comprehensively analyzing its clinical, computed tomography (CT) imaging, and postoperative pathological and genetic features.

Methods:

The clinical, CT imaging, and postoperative pathological features of different classifications of nodular lung adenocarcinoma were retrospectively analyzed through univariate and multivariate statistical methods.

Results:

There were 132 patients with nodular lung adenocarcinoma enrolled. Firstly, compared with ground-glass nodular lung adenocarcinoma, solid nodular lung adenocarcinoma was more common in women [odds ratio (OR), 3.662; 95% confidence interval (CI) 1.066-12.577] and older adults (OR, 1.061; 95% CI 1.007-1.119), and CT signs were mostly lobulation (OR, 4.957; 95% CI 1.714-14.337) and spiculation (OR, 8.214; 95% CI 2.740-24.621); the mean CT (CTm) value of solid nodular lung adenocarcinoma was significantly higher than that of ground-glass nodular lung adenocarcinoma, and the optimal diagnostic threshold was -267.5 Hounsfield units (HU). Secondly, the maximum diameter of nodule size (NSmax) of invasive adenocarcinoma (IAC) was significantly greater than that of minimally IAC (MIA; OR, 6.306; 95% CI 1.191-33.400) or atypical adenomatous hyperplasia (AAH)/adenocarcinoma in situ (AIS; OR, 189.539; 95% CI 4.720-7,610.476), and the optimal diagnostic threshold between IAC and MIA was 1.35 cm; the CTm value of IAC was significantly higher than that of MIA, and the optimal diagnostic threshold was -460.75 HU. Thirdly, lepidic-predominant adenocarcinoma (LPA) manifest more commonly as pure ground-glass nodule (pGGN; OR, 6.252; 95% CI 1.429-27.358) or mixed ground-glass nodule (mGGN; OR, 4.224; 95% CI 1.223-14.585). Moreover, the mutation rate of epidermal growth factor receptor (EGFR) in IAC was 70.69% (41/58). The EGFR mutation rates of mGGNs (OR, 8.794; 95% CI 1.489-51.933) and solid nodules (SNs; OR, 12.912; 95% CI 1.597-104.383) were significantly higher than that of pGGNs. Furthermore, compared with those of micropapillary-predominant adenocarcinoma (MPA), solid-predominant adenocarcinoma (SPA), or invasive mucinous adenocarcinoma (IMA), there were significantly higher EGFR mutation rates in acinar-predominant adenocarcinoma/papillary-predominant adenocarcinoma (APA/PPA; OR, 55.925; 95% CI 4.045-773.284) and LPA (OR, 38.265; 95% CI 2.307-634.596).

Conclusions:

Different classifications of nodular lung adenocarcinoma have their own clinicopathological and CT imaging features, and the latter is the main predictor.