Mediastinal mass

Background

• Normal structures in the mediastinum include:
  • Anterior: fat, lymph nodes, thymus or thymic remnant, heart, ascending aorta
  • Middle: trachea, bronchi, lymph nodes, esophagus, and descending aorta
  • Posterior: paravertebral soft tissue

Etiologies

Anterior Mediastinal Mass

• Thymic lesion, including thymoma, thymic carcinoma, thymic carcinoid, and thymic cyst
• Lymphoma, particularly Hodgkin disease, mediastinal large cell non-Hodgkin lymphoma, and lymphoblastic non-Hodgkin lymphoma
• Teratoma or dermoid cyst
• Germ cell tumour, including seminoma and non-seminomatous tumour (yolk sac tumour, embryonal carcinoma, and choriocarcinoma)
• Substernal goiter or ectopic thyroid tissue
• Parathyroid adenoma
• Lipoma and liposarcoma
• Fibroma and fibrosarcoma
• Foramen of Morgagni hernia
• Fibrosing mediastinitis, including histoplasmosis and tuberculosis, autoimmune disorders, medication effects, and radiation exposure

Middle Mediastinal Mass

• Pericardial cyst
• Lymphadenopathy from lymphoma, sarcoidosis, or metastatic lung cancer
• Enteric cyst
• Esophageal tumour
• Vascular mass or ectasia

Posterior Mediastinal Mass

• Neurogenic tumour, including neurofibroma, neurilemmoma, neurosarcoma, ganglioneuroma, ganglioneuroblastoma, neuroblastoma, chemodectoma, pheochromocytoma
• Meningoceles
• Thoracic spine lesions, including Pott disease