Accounting for 30% of mediastinal masses: (A + B)
- Adenopathy (infection [bacterial pneumonia, granulomatous (histoplasmosis, tuberculosis)], neoplasm [leukemia / lymphoma (Hodgkin, Non-Hodgkin), metastases])
- Aneursym (left atrial, dilated vessel), Achalasia
- Bronchopulmonary foregut malformation (esophageal duplication, bronchogenic cyst, pulmonary sequestration)
Approach to differential diagnosis of middle mediastinal masses:
- CT of the chest with contrast will help you to rapidly distinguish whether the mass you are seeing is due to:
- Adenopathy from a bacterial or granulomatous infection or a neoplasm such as leukemia / lymphoma
- Aneursym of one of the great vessels or heart
- Bronchopulmonary foregut malformation. While esophageal duplication and bronchogenic cyst are indistinguishable via imaging, pulmonary sequestration can be diagnosed if it has a feeding vessel arising from the aorta
Pediatric Imaging 