Contrast-enhanced Ultrasound Features of Mediastinal Lymphomas and Thymic Epithelial Tumors.

OBJECTIVES:To summarize the contrast-enhanced ultrasound (CEUS) features of mediastinal lymphomas and thymic epithelial tumors (including thymomas and thymic carcinomas) and to explore the value of CEUS in the differential diagnosis of lymphomas and thymic epithelial tumors.METHODS:Sixty-nine patients with 69 mediastinal lesions who underwent CEUS and had disease confirmed by histopathology were enrolled in the study. There were 33 cases of lymphoma, 19 cases of thymic carcinoma, and 17 cases of thymoma. CEUS features, including the enhancement pattern, enhancement distribution, enhancement time, inner necrosis status, wash out pattern, and vascular morphology, were evaluated in each group.RESULTS:Thymomas often presented with homogeneous (88.2%, 15/17) and late (88.2%, 15/17) enhancement and a low rate of inner necrosis (17.6%, 3/17). Late (73.7%, 14/19), heterogeneous (68.4%, 13/19), and centripetal (63.2%, 12/19) enhancement were more often observed in thymic carcinoma, as was a high rate of inner necrosis (78.9%, 15/19). Lymphomas showed a homogeneous enhancement rate of 57.6% (19/33) and a late enhancement rate of 54.5% (18/33). The rate of inner necrosis for lymphomas was 45.5% (15/33). The diagnostic accuracy of this finding for distinguishing thymic epithelial tumors from lymphomas was 63.8%, the sensitivity was 80.6%, and the specificity was 45.5%. Enlarged blood vessels were a feature specific to lymphomas, while small vessels arranged in a comb shape was a feature specific to thymic epithelial tumors.CONCLUSION:This study describes the CEUS features of common mediastinal tumors and may stimulate further studies in this field.