<prompt> Most common posterior mediastinal tumor is:NeurofibromaThymomaGerm cell TumorsAortic aneursym  <response>: Ans: A Neruofibroma Ref: Bobbins Pathologic basis of Disease, 8th ed.Explanation:Mediastinal TumorsAnterior front mediastinumGerm cell Tumors - The majority of germ cell neoplasms 60 to 70 are benign and are found in both males and females.Lymphoma - Malignant tumors that include both Hodgkins disease and non Hodgkins lymphoma.Thymoma and thymic cyst - The most common cause of a thymic mass, the majority of thymomas are benign lesions that are contained within a fibrous capsule. However, about 30 of these may be more aggressive and become invasive through the fibrous capsule.Mediastinal Thyroid mass - Usually a benign growth, such as a goiter, these can occasionally be cancerous.Middle mediastinumBronchogenic cyst - A benign growth with respiratory origins.Mediastinal Lymphadenopathy - An enlargement of the lymph nodes.Pericardial cyst - A benign growth that results from an out-pouching of the pericardium the hearts lining.Mediastinal Thyroid mass - Usually a benign growth, such as a goiter. These types of tumors can occasionally be cancerous.Tracheal tumors - These include tracheal neoplasms and non-euplastic masses, such as tracheobronchopathia osteochondroplastica benign tumors.Vascular abnormalities including aortic aneurysm and aortic dissection.Posterior back mediastinumExtramedullary haematopoiesis - A rare cause of masses that form from bone marrow expansion and are associated with severe anemia.Mediastinal Lymphadenopathy- An enlargement of the lymph nodes.Mediastinal Neuroenteric cyst- A rare growth, which involves both neural and gastrointestinal elements.Mediastinal Neurogenic neoplasm- The most common cause of posterior mediastinal tumors, these are classified as nerve sheath neoplasms, ganglion cell neoplasms, and paraganglionic cell neoplasms. Approximately 70. of neurogenic neoplasms are benign.Oesophageal abnormalities including achalasia oesophageal, oesophageal neoplasm and hiatal hernia.Paravertebral abnormalities including infectious, malignant and traumatic abnormalities of the thoracic spine.Mediastinal Thyroid mass- Usually a benign growth, such as a goiter, which can occasionally be cancerous. Vascular abnormalities - Includes aortic aneurysms. 