Subcutaneous emphysema and pneumomediastinum due to foreign body aspiration.

Pneumomediastinum is a result of perforation of the tracheobronchial tree. When air enters the interstitial space, air diffuses along the perivascular sheaths toward the mediastinum. If an air leak persists, subcutaneous emphysema occurs owing to the continuous leakage of air. Foreign body aspiration rarely causes pneumomediastinum and subcutaneous emphysema. Removal of the foreign body results in a resorption of air and the resolution of symptoms. Here, we present a rare case of foreign body aspiration in a 2-year-old patient who presented with pneumomediastinum and subcutaneous emphysema.