Incidental mediastinal masses detected on chest computed tomography scans during the COVID-19 pandemic.

Objectives: The prevalence of mediastinal masses in large-scale populations in China has been rarely reported. During COVID19 pandemic, many incidentalomas were reported due to the large amount of chest computed tomography scan performed in emergency setting.

Methods: Retrospective analysis of emergency chest computed tomography scans (February 2020-February 2021) for COVID-19 screening, including mediastinal abnormalities (excluding lymph nodes, dysplasia, pneumomediastinum and other non-mass alterations), with computed tomography features, diagnostic workup and 1 year follow-up data were reviewed.

Results: Of the 40 112 patients [mean age 54.5 (17.2) years; male-to-female ratio 1.02:1] screened for COVID-19, 293 (0.73%) had mediastinal masses of which 223 (0.56%) located in the anterior mediastinum. As participants aged, the prevalence tended to increase (P < 0.001). The prevalence was not different between the sexes (P = 0.635). An oval shape, anterior mediastinal location, and thymus involvement were the most common computed tomography characteristics. Surgery confirmed 11.3% (33 of 293) of nodal lesions, with a benign to malignant ratio of 51.4: 48.5. A computed tomography scan follow-up was conducted in 32.3% (84/260) of the patients, and in 82.1% (69/84) of cases the lesion was stable. Additionally, mediastinal masses were detected in 7.7% (20/260) of elderly patients who passed away soon after their primary disease worsened.

Conclusions: In Chinese COVID-19 screening chest computed tomography, the prevalence of all mediastinal masses and anterior mediastinal masses was 0.73% and 0.56%, respectively. Findings support risk-stratified management: growing/suspicious lesions warrant intervention versus surveillance for stable masses. Standardized protocols and multidisciplinary consensus are critical.