CT findings of primary non-teratomatous germ cell tumors of the mediastinum--a report of 15 cases.

OBJECTIVE

To analyze computed tomography (CT) features of primary non-teratomatous germ cell tumors of the mediastinum and to improve the diagnostic efficacy of CT for such tumor.

METHODS

Fifteen patients with primary non-teratomatous germ cell tumors of the mediastinum, proven pathologically, were enrolled. All patients underwent non-enhanced and contrast-enhanced CT examinations. The CT features, including location, size, shape, edge, CT attenuation, involvement of adjacent structure and local or distant metastasis of each lesion were retrospectively analyzed.

RESULTS

Each case showed single mass, a total of 15 masses. 11 masses arose within the left anterosuperior mediastinum and 4 masses arose within the right anterosuperior mediastinum. 10 masses appeared lobulated and ill-circumscribed, and 5 masses appeared rounded or oval and well-circumscribed. The maximal diameter of all the masses ranged from 5 cm to 16 cm (mean, 11 cm). 12 masses revealed heterogeneous attenuation on non-enhanced CT images with patchy low-attenuation foci and stippled calcification, and showed moderately heterogeneous enhancement after contrast administration. 3 masses of the patients with seminoma revealed homogeneous attenuation on non-enhanced CT images and showed lightly homogeneous enhancement after contrast administration. Pericardial effusion, pleural effusion and involvement of adjacent vascular structures were observed in 6, 5 and 10 cases, respectively. Pulmonary metastasis were observed in 3 cases.

CONCLUSIONS

The characteristic CT findings of primary non-teratomatous germ cell tumors of the mediastinum include bulky, ill-circumscribed, lobulated masses, heterogeneous attenuation with low-attenuation foci and calcification on non-enhanced CT images and heterogeneous enhancement after contrast administration. Seminomas may show homogeneous attenuation and homogeneous enhancement after contrast administration. The tumor is apt to involve pericardium, pleura and adjacent vascular structure and develop distant metastasis. Primary non-teratomatous germ cell tumors should be considered when anterosuperior mediastinal masses are detected with these findings, especially in young males.