Commonest mass in the middle mediastinum is ?

Ans. is 'c' i.e., Lymph node mass Mediastinal masses 1. Anterior mediastinum : - The anterior mediastinum contains the following structures : thymus, lymph nodes, ascending aoa, pulmonary aery, phrenic nerve and thyroid. Thymoma is the most common anterior mediastinal mass. Anterior mediastinal masses include : ? o Thymoma o Aneurysm of ascending aoa o Retrosternal thyroid o Lymphoma o Pericardial cyst o Morgagni hernia o Teratoma germ cell 2. Middle mediastinum : - The middle mediastinum contains the following structures: lymph nodes, trachea, esophagus, azygos vein, Vena cavae, posterior hea and aoic arch. The most common middle mediastinal mass is enlarged lymph nodes (Lymphadenopathy). Middle mediasinal mass include. o Lymph node enlargement o Pericardial cyst o Coronary/pulmonary aneurysm o Bronchogenic cyst o Aoic arch aneurysm o Azygous vein enlargement Note : Though most common middle mediastinal mass is enlarged lymph nodes, In children the most common middle mediastinal mass is duplication cysts (Bronchogenia cyst or esophageal duplication cysts or neuroenteric cysts). 3.Posterior mediastinum : - The posterior mediastinum contains the following structures : Sympathetic ganglic, nerve roots, lymph nodes, parasympathetic chain, thoracic duct, descending thoracic aoa, Small vessels and the veebrae, Most common masses in posterior mediastinum are neurogenic in nature. These can arise from the sympathetic ganglia (e.g., neuroblastoma) or from nerve roots (e.g., Schwannoma or neurofibroma). Posterior mediastinal masses include. o Neurogenic tumor (neuroblastoma, o Lymph node enlargement o Anterior meningocele Schwannoma, neurofibroma) o Neurenteric cyst o Bochdalek hernia o Aneurysm of descending aoa o Overall most common mediastinal masses are neurogenic tumors (20%) followed by thymomas (19%), primary cysts (18%), lymphomas (13%) and germ cell tumors (10%). o Most of the mediastinal masses are located in the anterior mediastinum followed by the posterior (25%) and middle (19%).