Proportion and characteristics of transient nodules in a retrospective analysis of pulmonary nodules

Abstract

Background: Pulmonary nodules manifest as pure or mixed ground glass opacities (GGOs), or solid nodules. Methods: We retrospectively surveyed 317 cases with pulmonary nodules to observe the proportion and predictive factors of transient lesions in patients with pulmonary nodules. Results: At the initial computed tomography scan, 63.7% showed solid nodules, while 20.2% had mixed GGOs and 16.1% of cases manifested as pure GGOs. Nodules from 114 cases (36%) disappeared or decreased in size during follow up, while in 203 cases (64%), they did not change or became enlarged. During follow up, more than half of the GGOs resolved (66.7% in pure GGOs, 54.7% in mixed GGOs), while only 22.3% of solid nodules resolved. Between transient and persistent pulmonary nodules, significant differences were observed in age, gender, smoking history, presence of eosinophilia, size, and radiologic attenuation of nodules (solid or GGO). In multivariate analysis, age (Յ55 years), size of nodules (>15 mm), eosinophilia, and GGO were significant independent predictors of transient nodules. The main causes of transient nodules were pneumonia or eosinophilic pulmonary infiltrates. Conclusion: Thirty-six percent of pulmonary nodules resolved spontaneously or with medical treatment. Transient nodules showed different clinical and radiological characteristics from persistent nodules.

Features for Predicting Absorbable Pulmonary Solid Nodules as Depicted on Thin-Section Computed Tomography

“… 19 , 20 In this study, patients younger (≤55 years) was an independent predictor of absorbable PSNs, consistent with earlier findings. 14 However, there was no significant difference for gender and smoking history between patients with absorbable and malignant PSNs. Thus, only age may be an important clinical factor in determining whether nodules are absorbable or malignant.…”

Implications of the updated Lung CT Screening Reporting and Data System (Lung-RADS version 1.1) for lung cancer screening

“…Notably, solid nodules are far less likely to resolve than GGNs or part solid nodules (PSNs) (48). Yu et al found within their cohort that only 22% of solid nodules resolved during follow-up compared with 67% of PGGNs and 55% of mixed GGNs (48). Both Yu's and…”

“…Lee's groups found that age ≤55 years and blood eosinophilia were predictors for nodule resolution (48,49). A multiplicity of PSNs, a large solid component, and irregular borders were also predictors for resolution (49) (Figure 4).…”

“…A multiplicity of PSNs, a large solid component, and irregular borders were also predictors for resolution (49) (Figure 4). The time to resolution for GGNs, PSNs, and solid nodules is unfortunately not clear (47)(48)(49). Zhao et al (47) found that of nodules that resolved, 75 of 97 did so by the 3 month follow-up CT, and Lee et al (49) defined transience as reduction or resolution of PSNs at 3 months.…”

Pure ground-glass nodules: are they really indolent?

“…The first step when discovering a pGGN is, according to the latest guidelines (12), to control it by CT 6 to 12 months later, enabling to exclude from 33% to 67% of benign inflammatory and infectious lesions manifesting as pGGNs (13,14). Once this step is done, the main issue we have today is that the tools currently available to differentiate extremely slow growing in situ or minimally invasive lesions from faster growing invasive adenocarcinomas in persistent pGGNs remain relatively limited.…”