Differential diagnosis of anterior upper mediastinal expansions by contrast-enhanced computed tomography.

This study investigated the potential of contrast-enhanced CT in the differential diagnosis of the most common anterior upper mediastinal expansions. CT examinations of 29 patients with an upper anterior mediastinal mass lesion of unknown origin were reviewed retrospectively and compared with the clinical data obtained. The density, contrast enhancement and invasive nature of the tumors were recorded. Thyroid tissue was enhanced most and lymphomas least. Contrast medium injection helped to distinguish great vessels and cystic lesions from surrounding areas. Thyroid tissue was most heterogeneous and lymphomas most homogeneous. All except one of the malignant neoplasms (a lymphoid mass lesion) were infiltratory in nature. Contrast-enhanced CT gives clues as to the origin of a neoplasm and whether it is benign or malignant.