Benign and Malignant Part-Solid Nodules: Differentiation Via Thin-Section Computed Tomography

Abstract Background: Pulmonary part-solid nodules (PSNs) are reported to have a high possibility of malignancy, while benign PSNs are not rare. This study aimed to reveal the differences between benign and malignant PSNs by comparing their thin-section CT features.Methods: Patients with PSNs confirmed by postoperative pathological examination or follow-up (at the same period) were retrospectively enrolled from March 2016 to January 2020. The clinical data of patients and CT features of benign and malignant PSNs were reviewed and compared. The binary logistic regression analysis was performed to reveal predictors of malignant PSNs.Results: A total of 119 PSNs in 117 patients (mean age, 56 years ± 11 [standard deviation]; 70 women) were evaluated. Of the 119 PSNs, 44 (37.0%) were benign, and 75 (63.0%) were malignant (12 adenocarcinomas in situ, 22 minimally invasive adenocarcinomas, and 41 invasive adenocarcinomas). Between benign and malignant PSNs, there were significant differences in patients’ age and smoking history. Regarding CT characteristics, malignant lesions and benign lesions significantly differed in CT features of whole nodule, internal solid component, and peripheral ground-glass opacity. The binary logistic regression analysis revealed that well-defined border (odds ratio [OR], 4.574; 95% confidence interval [CI], 1.186-17.643; P=0.027) and lobulation (OR, 61.739; 95% CI, 5.230-728.860; P=0.001) of nodule, and irregular shape (OR, 9.502; 95% CI, 1.788-50.482; P=0.008) and scattered distribution (OR, 13.238; 95% CI, 1.359-128.924; P=0.026) of internal solid components were significant independent predictors distinguishing malignant PSNs.Conclusions: Well-defined and lobulated PSNs with irregular and scattered solid components have a high probability of being malignant.