No abstract

•The most common cause of anterior mediastinal masses is thymoma that is often associated with myasthenia gravis and other paraneoplastic syndromes.• Radiographically, thymic tumors and lymphoma present as smooth or lobulated masses in the upper half of the chest. With the presence of calcification, the lesion is most likely of thymic origin since untreated lymphoma rarely calcifies. Mediastinal and hilar lymph nodes are more often enlarged in lymphoma. GCTs, with the exception of NSGCT, tend to be more heterogeneous with multiple densities. NSGCTs are similar to GCTs with the absence of fat and calcification.• Neurogenic tumors include those arising from the peripheral nerves, such as schwannomas, neurofibromas and their malignant counterparts: those arising from the sympathetic ganglia, such as ganglioneuroma, ganglioneuroblastoma and neuroblastoma, and those arising from the parasympathetic ganglia such as pheochromocytoma and chemodectoma.• Neurogenic tumors are well-defined rounded masses in the costovertebral junction with cortical disruption of the adjacent ribs and vertebrae. They have low density on CT and enhance after contrast administration, most strikingly seen with the paragangliomas. MRI will demonstrate spinal cord involvement.• Definitive diagnosis of a mediastinal mass involves histologic sampling that can be performed via US or CT-guided percutaneous biopsy, as well as other imageguided or surgical techniques.• PET-CT is an evolving imaging technique that is used for re-staging of lymphoma and seminoma and likely NSGCT. Therapy monitoring is a promising new application of PET-CT that is currently under research.