Multislice computed tomography performance in differential diagnosis of high-density thymic cyst and thymoma in lesions less than 3 cm

Background: This study was conducted to evaluate the performance of multislice computed tomography (MSCT) to diagnose high-density thymic cysts and thymomas in lesions measuring < 3 cm.

Methods: The records of 42 patients admitted to Ningbo No. 2 Hospital with an anterior mediastinal mass (diameter < 3 cm) suspected of carcinoma originating from the thymus were retrospectively analyzed. All patients underwent surgery and pathological examination. Twenty-eight were diagnosed with thymic cysts and 14 with thymoma. The features of thymic cysts and thymomas revealed on MSCT were compared.

Results: Mediastinal masses with a triangular or teardrop shape and a straight mediastina-lung border were more likely to be diagnosed as thymic cysts (P < 0.05), while those with a bulging nodule-lung border were more likely thymomas (P < 0.05). Using the CT value as a reference for differential diagnosis, the diagnostic sensitivity, specificity, and area under the receiver operating characteristic curve for CT values of non-contrast CT images, enhanced CT values, and ΔCT values were 0.65 (0.47-0.84), 0.95(0.86-1.00), and 0.96 (0.89-1.00), respectively.

Conclusion: MSCT of high-density thymus gland nodules (maximum diameter ≤ 3 cm) can reveal specific features that could be helpful for differential diagnosis.