We report a rare case of epidural pneumatosis associated with pneumomediastinum that occurred at rest. A 17-year-old male had spontaneously felt shortness of breath while attending class during the day. Chest and neck CT revealed interstitial free air collection along the right pulmonary vascular sheath. It was speculated that some cough or strain-induced increase in intra-alveolar pressure in the alveoli along the right upper lobe caused free air leaks from the ruptured alveoli, which accumulated along the bronchovascular tissue sheath and moved into the mediastinum and subcutaneous area, especially in the right neck, right anterior chest wall, and right axillary region. CT also demonstrated subcutaneous emphysema extended into the epidural space through the intervertebral foramen. He exhibited a benign self-limited course.