Rare mediastinal masses - imaging review

Mediastinal masses span a wide histopathological and radiological spectrum. Apart from primary thymic/thyroid masses and lymphomas, all other mediastinal masses can be considered rare tumors. Chest radiography and Computed tomography (CT) are helpful to characterize the mass and can reach a diagnosis or a close differential diagnosis. MRI in special situations can depict the pericardial/vascular invasion better, and diffusion studies can recognize benign from the malignant mass. The imaging details of 15 histopathologically proven cases of rare mediastinal tumors are described. Neuroblastoma (NB) (n = 3) was the most common among the rare masses. Three were sarcomas, one liposarcoma, one synovial sarcoma, one spindle-cell tumor and one Hemangiopericytoma (HPC). Lymphoma presenting as a single mass, neuroendocrine tumor (NET) of the anterior mediastinum, paraganglioma of the posterior mediastinum (one each) were seen.The imaging features of these rare mediastinal masses have to be kept in mind for appropriate diagnosis.