Objective:

To investigate the computed tomography (CT) and clinical features of thymic neuroendocrine tumor (TNET) and improve the diagnostic accuracy of TNET.

Methods:

The clinical and CT data of 22 patients with TNET confirmed by histopathology were retrospectively reviewed. CT images were analyzed

included lesion location

size

shape

density

cystic degeneration

necrosis

calcification

pattern of enhancement

surrounding

tissue invasion

mediastinal or hilar lymph node metastasis (short diameter ＞10 mm) and distant metastasis.

Results:

According to the histopathology results

there were 1 case of typical carcinoid

14 cases of atypical carcinoid

3 cases of small cell carcinoma

and 4 cases of large cell neuroendocrine carcinoma. CT features: the lesions were mainly located in the anterior mediastinum

and the median maximum diameters of lesions were 6.2 cm (range 2.4-10.0 cm) in the axial images. 5 lesions were lobulated

9 lesions were irregular shape and 8 lesions were round-alike. 4 lesions with uniform density and 18 lesions with uneven density. 17 cases contained necrosis

5 cases contained cystic degeneration and 6 cases contained calcification. Enhanced CT scan: 14 cases showed mild enhancement

7 cases showed moderate enhancement and 1 case showed significant enhancement

6 cases showed intratumoral blood vessels. Surrounding tissue invasion: there were 12 cases of pleura invasion

13 cases of pericardium invasion

10 cases of pulmonary invasion

18 cases of mediastinal vessels invasion. There were 11 patients with mediastinal lymph node metastasis

2 patients with supraclavicular fossa

heart phrenic hornarea and retroperitoneal lymph node metastasis

4 patients with lung metastasis and 3 patients with pleural metastasis.

Conclusion:

TNET is more common in elderly male patients

the CT findings of TNET are masses with large anterior mediastinal volume

and the necrotic cystic changes are common. There is mild to moderate enhancement in post-contrast scan

the tumor is aggressive and tends to invade the surrounding structures and the metastasis is common. CT plays an important role in differential diagnosis and preoperative evaluation of TNET.