1Department of Radiology, Osaka University Medical School, 2First Surgical Department, Osaka University Medical School, 3Present Address: Department of Radiology, Kansai Rosai Hospital, 4Present Address: Department of Radiology, Shinshu University Medical School
In order to know the clinical usefullness and limitation of ultrasonography in making diagnosis of mediastinal tumors, ultrasonographic findings were studied in 31 patients with anterior mediastinal tumors (13 thymomas, 11 teratomas, and 7 malignant lymphomas). Nine of 13 thymomas were demonstrated as homogeneous, solid tumors and the other 4 thymomas were mixed pattern tumors. The mixed pattern thymomas were large thymomas more than 6 cm in diameter, and invasive. Teratomas were visualized as solid, cystic, or mixed pattern tumors. Eight cystic teratomas were sonographically visualized as various kinds of mass, 2 cystic, 2 solid and 4 mixed. Three solid teratomas with some small cysts were demonstrated as mixed tumors. These complexity of echo pattern was partially due to the pathological complexity of teratomas, and partially due to the fact that some cystic lesions were visualized as solid or mixed pattern lesions when the content of the cyst was non-serous fluid, sebum, or muddy material. Seven malignant lymphomas were visualized as solid or mixed pattern tumors, 2 homogeneous solid, 3 inhomogeneous solid, and 2 mixed. There was no relationship between echo pattern and histological types of malignant lymphoma. One case with tumor infiltration around the great vessels and another case with chest wall invasion were nicely demonstrated on ultrasonography.