Mediastinal tumour symptoms vary depending on its location and severity. A mediastinal tumour in the posterior region can result in numbness or pain in the spine, if it’s in contact with the spinal cord. A tumour in the middle mediastinum can cause shortness of breath, as it affects the lungs. A tumour in the anterior region can create a sense of stuffiness or fullness in the chest, with a growth taking up what would usually be empty space.