To investigate the clinical features and CT findings of thymic carcinoma.

The clinical features and imaging of 43 patients with thymoma carcinoma confirmed by pathology were retrospectively analyzed, by studying the tumor location, shape, size, edge, density, enhancement mode, relationship between tumor and adjacent tissues and organs, pericardial /pleural effusion, lymph node /distant metastasis on CT.

The primary thymic carcinoma was more common in the middle-aged and elderly, with an average age of (55.3 ± 13.0) years. The main clinical symptoms were chest pain and chest tightness, followed by shortness of breath and cough. Male is more common than female(2.91︰1). The location of all the irregular tumor were located in the anterior mediastinum, include lateral growth was found in 38 cases and median growth in 5 cases. The maximum diameter of the mass was 3.8~13 cm, The average size was (7.2±3.5) cm. All the tumors were invasive growth, the boundary was not clear, and the surrounding fat space disappeared and blurred. The average CT value on plain scan was(32.3±10.7)Hu. On the plain scan, the density of the mass was not uniform in 39 cases, and uniform in 4 case. Patchy necrosis are seen in most lesions. Calcification was found in 17 cases. Tumors encircling macrovasular or pericardium were found in 42 cases, invaded the lung tissue were found in 13 cases, and pericardial /pleural effusion were found in 29 cases. There were 25 cases with lymph node metastasis in mediastinum and 12 case with distant metastases. On the contrast-enhanced scan, the solid part of tumor almost showed moderately enhancement, and the necrosis in the mass showed no enhancement. The mean CT value of the arterial phase and venous phase was about (58.2±16.1)Hu and(64.0±18.6)Hu, respectively.

The thymic carcinoma is a rare mediastinal malignant tumor with no special symptom. The main manifestations were irregular soft tissue mass growing laterally in the anterior mediastinum with uneven density on CT. The enhancement was mainly moderately enhanced. The mass often invaded adjacent tissues and organs. Multi slice spiral CT has certain characteristics, which can not only show the internal structure of the tumor, but also show the relationship with adjacent structures. It is of great significance for the correct preoperative diagnosis and the choice of clinical treatment.