Diseases of the Mediastinum and Associated Conditions

Abstract

This Discussion includes those diseases and conditions which may produce abnormal shadows in and adjacent to the mediastinum. Cardiac and vascular lesions are not included except where they need to be differentiated from other mediastinal masses. Those diseases in which the major roentgenological manifestations are in the pulmonary parenchyma are discussed briefly, if at all, since the roentgen diagnosis is based more on the pulmonary changes than on mediastinal variations. As with other regions of the body, it is possible to classify mediastinal lesions in various ways. The classification given below is based on the anatomical structures contained within the mediastinum and has the advantage of relative simplicity. Also it is essential in the differential diagnosis to determine, first of all, the anatomical division of the mediastinum involved and, second, if possible, the structure or structures which may have given rise to the abnormality in question. Once this has been accomplished, the diagnostic possibilities become limited. I. Diseases of the mediastinal lymph nodes Infections Non-specific lymphadenopathy Acute and chronic Fungus infections Tuberculosis Primary tuberculosis Hyperplastic tuberculosis Associated with caseous tuberculosis Associated with erythema nodosum Boeck's sarcoid Asymptomatic form Tumors of the mediastinal lymph nodes Primary malignant Hodgkin's disease, lymphosarcoma, leukemia, aleukemic leukemia Metastatic tumors II. Primary tumors of mediastinum other than lymph node tumors Benign Lipoma, fibroma, dermoid cyst and teratoma, chondroma, ganglioneuroma, neurofibroma, cystic hygroma Malignant Fibrosarcoma, neurofibrosarcoma, liposarcoma, thymoma III. Mediastinitis Acute mediastinitis Acute diffuse mediastinitis Acute mediastinal abscess Chronic mediastinitis Chronic mediastinal abscess Chronic diffuse or fibrous mediastinitis Mediastinopleural (paramediastinal) effusion Mediastinal emphysema IV. Diseases of the thyroid and thymus Thymic hyperplasia in children Thymic tumors Enlarged thyroid, substernal thyroid and intrathoracic goiter V. Diseases of the spine Tuberculosis and other infections Tumors VI. Cardiovascular lesions Enlarged left auricle Aneurysm of aorta Right-sided aorta Pulmonary artery dilatation Aneurysm of innominate artery VII. Diseases of esophagus and stomach Cardiospasm Esophageal hiatus hernia and thoracic stomach VIII. Bronchogenic carcinoma Anatomy Of The Mediastinum The mediastinum is defined as that space lying between the right and left pleurae, in and near the median sagittal plane of the chest (Fig. 1). It extends from the sternum in front to the vertebral column behind and contains all the thoracic viscera except the lungs. For convenience in description anatomists usually divide it into four parts, the superior, anterior, middle, and posterior spaces (4).