TOPICS: Heart, thymus, lymph nodes, esophagus, aorta, superior mediastinum, inferior mediastinum, mediastinal masses, anterior mediastinum, thyroid, thymoma, teratoma, lymphoma, middle mediastinum, esophageal carcinoma, metastases, hiatal hernia, bronchogenic cysts, posterior mediastinum, neurogenic tumor, multiple myeloma, mediastinitis, cardiothoracic procedures, esophageal perforation, chronic mediastinitis, fibrosing mediastinitis, Histoplasma capsulatum, idiopathic fibrosing mediastinitis, wegener's granulomatosis, radiation therapy, sternal wound drainage, pneumomediastinum, spontaneous, pulmonary bleb, trauma, iatrogenic, boerhaave syndrome, Hamman sign, subcutaneous emphysema