Primary aortic myxofibrosarcoma mimicking thrombus: findings on CT, MRI, and angiography.

Aortic sarcoma is a rare vascular malignancy. We report a case of primary aortic myxofibrosarcoma mimicking thrombus. This neoplasm demonstrated no contrast enhancement on computed tomography or magnetic resonance imaging and was clinically suspected to represent a large thrombus, although aortic primary neoplasm was considered in the differential diagnosis on the basis of imaging. Biopsies of the aortic lesion and a concurrent brain lesion were consistent with the diagnosis of aortic myxofibrosarcoma with brain metastasis. This report highlights overlapping imaging features between primary aortic sarcoma and vascular thrombus and the importance of considering neoplastic conditions in the differential diagnosis of large intravascular soft tissue lesions.