Factors affecting the preoperative diagnosis of anterior mediastinal cysts

Although anterior mediastinal cysts are generally benign diseases, the preoperative diagnosis of these lesions is not necessarily accurate. This study aimed to investigate the factors affecting the preoperative diagnosis of anterior mediastinal cysts.

We conducted a retrospective analysis of 35 patients with pathologically diagnosed anterior mediastinal cysts (20 thymic cysts, 7 bronchogenic cysts, 5 pericardial cysts, and 3 others) that were resected at our hospital and evaluated their preoperative diagnosis, cyst size, and fluid content.

Eighteen, 15, 1, and 1 patient(s) were preoperatively diagnosed with cystic disease, thymoma, thymic cancer, and teratoma, respectively. Cysts were significantly larger in the correct diagnosis group (40.2 ± 18.8 mm) than in the incorrect diagnosis group (21.1 ± 10.4 mm) (p = 0.0011). The cut-off value of the cyst size which separates these groups, as indicated by the receiver operating characteristic curve, was 28 mm, with a sensitivity and specificity of 0.722 and 0.823, respectively. The diagnostic accuracy for mucinous cysts was significantly lower (p < 0.001) than that for serous cysts.

The presence of cysts smaller than 28 mm and mucinous fluid content was possible factors resulting in inaccurate preoperative diagnosis.