纵隔生殖细胞肿瘤40例的CT表现

CT Findings of Germ Cell Tumors of Mediastinum: A Report of 40 Cases

【目的】分析40例纵隔生殖细胞肿瘤的CT征象,提高其CT诊断准确性。【方法】回顾性分析40例病理证实的纵隔原发生殖细胞肿瘤的CT资料,24例为畸胎瘤,16例为非畸胎类生殖细胞肿瘤,40例均行CT平扫和增强扫描,观察征象包括:发病部位,肿瘤大小,轮廓,边缘,平扫和增强扫描CT值,对于临近结构的侵犯,有无远处转移。【结果】40例肿瘤均位于前纵隔,肿瘤的最大径为5～16 cm;24例畸胎瘤边界清楚,呈类圆形,CT平扫20例可见脂肪密度影和钙化,增强扫描轻度强化,4例呈均匀水样密度,肿瘤壁薄均匀,见弧线状钙化,增强扫描未见强化。16例非畸胎类生殖细胞肿瘤分别呈分叶状,边界不清楚(11/16例)或类圆形,边界清楚(5/16例),13例肿瘤平扫密度不均匀,内见稍高于水密度的低密度灶或斑点状钙化,增强扫描不均匀强化,3例精原细胞瘤呈均匀密度,增强扫描均匀强化;分别有6例、6例、10例和3例非畸胎类生殖细胞肿瘤侵犯心包、胸膜、临近大血管和出现肺转移。【结论】纵隔生殖细胞肿瘤的常见CT征象为好发于前纵隔,肿瘤体积较大,畸胎瘤多数含有脂肪成分和钙化,CT容易诊断。非畸胎类生殖细胞肿瘤多呈分叶状,边界不清楚,CT平扫密度不均匀,增强扫描不均匀强化;精原细胞瘤可表现为均匀密度和均匀强化。非畸胎类生殖细胞肿瘤可侵犯心包、胸膜和临近大血管,并出现其他器官转移;诊断应当与胸腺瘤和淋巴瘤相鉴别。

[ Objective]To analyze computed tomography （CT） features of germ cell tumors of the mediastinum and to improve the diagnostic efficacy of CT for such tumor. [ Methods ] Forty patients with primary germ cell tumors of the mediastinum, and proven pathologically, were enrolled. All patients, including 24 patients with teratoma and 16 patients with non-teratomatous germ cell tumor, 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 ] All the masses arose within the anterior mediastinum and their maxima[ diameter ranged from 5 cm to 16 cm （mean, 11 cm）. 24 masses of patients with teratoma appeared rounded or oval and well-circumscribed, 20 of which revealed fat and calcification on non- enhanced CT images and showed light enhancement after contrast administration, the rest four masses revealed homogeneous water attenuation, and the capsule wall was thin and uniform with vaulted calcification on it. 11 and 5 masses of patients with non- teratomatous germ cell tumor appeared lobulated, ill-circumscribed and rounded or oval and well-circumscribed, respectively. 13 masses revealed heterogeneous attenuation on non-enhanced CT images with patchy low-attenuation foci whose attenuation is lightly larger than that of water and stippled calcification, and showed moderately heterogeneous enhancement after contrast administration. 3 masses of patients with seminoma revealed homogeneous attenuation and homogeneous enhancement after contrast administration. 6, 6, 10, and 3 cases of non-teratomatous germ cell tumor showed pericardial effusion, pleural effusion, involvement of adjacent vascular structures and pulmonary metastasis, respectively. [ Conclusions ] The characteristic CT findings of mediastinal germ celltumors reveal bulky masses in the anterior mediastinum. CT diagnosis for teratomas is easy because of the fat and calcification in the tumors. Most of non-teratomatous germ cell tumors show ill-circumscribed, lobulated masses, heterogeneous attenuation on notl- enhanced CT images and heterogeneous enhancement after contrast administration. Seminomas may show homogeneous attenuation and homogeneous enhancement after contrast administration. The non-teratomatous germ cell tumor is apt to involve pericardium, pleura and adjacent vascular structure and develop distant metastasis. The differential diagnosis between non-teratomatous germ cell tumor and thymoma, lymphoma is needed.