CT features of primary mediastinal neuroendocrine carcinoma

Abstract

Objective To investigate the CT features of primary mediastinal neuroendocrine carcinoma and improve the diagnostic accuracy. Methods CT findings of 12 patients with primary mediastinal neuroendocrine carcinoma diagnosed by clinic and pathology were retrospectively analyzed. The location, size, growth pattern, density, degree of enhancement, invasion of surrounding tissues and metastasis of the tumor were observed, a control analysis was performed. Results Among the 12 cases, 4 cases were located in the anterior superior mediastinum, 4 cases in the middle superior mediastinum and 4 cases in the middle mediastinum. There were 5 cases on the left side, 4 cases on the right side and 3 cases in the middle. The maximum diameter of the tumor ranged from 1.5 cm to 12.0 cm, with an average of (6.74±3.65) cm. The tumors were round or quasi-round in 6 cases, irregular in 6 cases, clear boundary in 9 cases and unclear in 3 cases. Uniform density was found in 6 cases. The density was heterogeneous in 6 cases, including necrosis and cystic degeneration in 4 cases, and fine-grained calcification in 1 case. The average CT value of plain scan was (38±4.8) HU. There was 1 case of perivascular growth, 2 cases of adjacent vascular compression, 3 cases of adjacent pleural invasion, and 6 cases of infiltrating the surrounding fat space. After contrast enhancement, all cases showed mild and moderate enhancement, including 4 cases with homogeneous enhancement and 8 cases with heterogeneous enhancement. After contrast enhancement, the mean CT value was (55±7.7) HU. There were 9 cases with mild enhancement and 3 cases with moderate enhancement. There were 3 cases with small linear abnormally enhanced vascular shadow in the tumor, and 4 cases with no enhancement both in the central necrosis and the cystic areas. There were 7 cases of typical carcinoid, 2 cases of atypical carcinoid, 2 cases of small cell carcinoma and 1 case of large cell neuroendocrine carcinoma. Conclusion Primary mediastinal neuroendocrine carcinoma is mainly located in the anterior-mediastinum. When the tumor is large, necrosis, cystic degeneration and invasive growth are easy to occur. The enhanced scan shows mild and moderate enhancement. Combined with clinical history, it can improve the accuracy of diagnosis. Key words: Mediastinal neoplasms; Neuroendocrine carcinoma; Tomography; X-ray computed