<prompt> The following is not the differential diagnosis of an anterior mediastinal massTeratomaNeurogenic tumorThymomaLymphoma  <response>: Anterior mediastinal masses:- Thymoma, Lymphoma, teratoma, Aneurysm of ascending aorta, pericardial cyst, retrosternal thyroid, Morgagni hernia.Middle mediastinal masses:- Lymph node enlargement, bronchogenic cyst, pericardial cyst, Aortic arch aneurysm, coronary pulmonary aneurysm, azygous vein enlargement. Tortuous innominate arteryKant.-IIPosterior mediastinal masses:- Neurogenic tumor neuroblastoma, schwannoma, neurofibroma, Aneurysm of descending aorta, lymph node enlargement, neuroenteric cyst, anterior meningocele, bochdolek hernia. 