Exploring the incidence rate and imaging differential diagnosis of anterior mediastinal lesions: an 11-year retrospective study based on 2,626 cases.

BACKGROUND

There are many complex types of anterior mediastinal lesions, and preoperative differential diagnosis is difficult in clinical practice. This study aimed to explore the incidence of different anterior mediastinal lesions and their differential diagnosis based on clinical and imaging features.

METHODS

We examined the local incidence of anterior mediastinal lesions and their different types in 2,626 patients with anterior mediastinal lesions. Among them, we explored the diagnostic utility of clinical, radiological, and pathological characteristics of 1,809 patients with complete imaging data.

RESULTS

The incidence rate of anterior mediastinal lesions was about 0.4%. Thymic epithelial tumors (TETs) showed the highest incidence rate (56.1%), with most patients aged 50-60 years. Lymphoma was the second most common lesion (16.3%). Age, average diameter, boundaries, calcification, average computed tomography (CT) value, surrounding tissues invasion (vascular, pleural, and lung), pericardial effusion, mediastinal enlargement of lymph nodes, and distant metastasis were identified as statistically significant risk factors for distinguishing TETs, with the areas under the curve (AUCs) of the training and validation sets of 0.94 and 0.93, respectively. Average diameter, edges, boundaries, average CT value, surrounding tissue invasion, and mediastinal lymph node enlargement were risk stratification factors for TETs [AUC: 0.865, 95% confidence interval (CI): 0.842-0.888; sensitivity, 72.0%; specificity, 85.6%]. Other malignant tumors included lymphoma, germ cell tumors, hematolymphoid tumors, and mesenchymal tumors. Benign lesions included simple cysts, mature teratomas, mesenchymal tumors, thymic tissue/hyperplasia, giant lymph node hyperplasia, inflammation, and retrosternal goiters.

CONCLUSIONS

We observed a low incidence rate of anterior mediastinal lesions. Age was associated with various types of anterior mediastinal lesions, with TETs showing the highest incidence. A systematic diagnostic approach for anterior mediastinal lesions can be developed based on the clinical and imaging features.