Pneumomediastinum and Subcutaneous Emphysema After Rapid Mediastinal Mass Regression

A 16-year-old boy presented with right cervical lymphadenopathy, facial redness, venous distention in the supine position, dizziness, shoulder pain and chest wall telangiectatic changes compatible with superior vena cava syndrome.Chest computed tomography (CT) showed a bulky anterior mediastinal mass compressing the airway and great vessels, with pleural and pericardial effusions (Figure 1a ).Blood work showed hyperuricemia and hyperleukocytosis, with peripheral blood flow cytometry showing T-lymphoblasts.He was therefore diagnosed with T-cell