This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
The following is not the differential diagnosis of an anterior mediastinal mass – 
Select and explain. 
A. Teratoma, B. Neurogenic tumor, C. Thymoma, D. Lymphoma
B: Neurogenic tumor
Answer: B: Neurogenic tumor 
Explanation: 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 artery(Kant.-II)
Posterior mediastinal masses:- Neurogenic tumor (neuroblastoma, schwannoma, neurofibroma), Aneurysm of descending aorta, lymph node enlargement, neuroenteric cyst, anterior meningocele, bochdolek hernia.