ABSTRACT
The mediastinum can be divided into three compartments-anterior, middle and posterior mediastinum (Fig. 18.1). The anterior mediastinum may be subcategorized into anterior and superior mediastinum. The superior portion of the anterior mediastinum lies above a plane extending from the sternal angle of Louis to the level of T4. The rest of the anterior mediastinum is in front of the anterior pericardium. The middle mediastinum is the space between the anterior portion of the pericardium back to the anterior portion of the vertebral bodies, and the posterior mediastinum is between the anterior portion of the vertebral body to the posterior portion of the vertebral body, i.e., to include the region of the paravertebral gutters. Tumors of the anterior mediastinum include thymoma, germ cell tumors (teratoma is one type), thyroid enlargement, and lymphoma. Middle mediastinal masses include pericardial cysts, bronchogenic cysts, lymphoma and mediastinal granulomas. Posterior mediastinal masses are predominantly tu mors of neurogenic origin.
