<prompt> Anterior mediastinal mass in 18 yrs old male -ThymomaEctopic glandAneunysmLymphoma  <response>: Ans. is a i.e., Thymoma Mediastinumo It is situated bw the lungs in the center o the thoraxo It is divided into 3 compartmentsy Anterior or Anterosuperioro It lies in front of the anterior pericardium trachea.y Middle mediastinum or Visceral compartmento It lives within the pericardial cavity including the tracheay Posterior mediastinum or paravertebral suleio It lies posterior to te post pericardium trachea Anatomic division of the mediastinumLocations of the common Mediastinal MassesAnterior mediastinumMiddle MediastinumPost. Mediastinumo Thymoma most common in Ant. med.o Cysts MC in Mid. Med.o Neurogenic tumors MC overall pleuropericardialo Meningoceleso Lymphoma bronchogenico Gastroenteric cysto Germ cell tumors enterogenouso Mesenchymal tumorso Mesenchymal tumors neuroenterico Pheochromocytomao Thyroid parathyroid masseso Vascular masses aneurysmo Lymphomao Lymph node enlargement including lymphomao Thymic cysto Mesenchymal tumorso Pheochromocytomao MC tumor in middle Mediastinum-Lymphoma 