Spontaneous pneumomediastinum originating from extensive subcutaneous emphysema.

A 76-year-old man with chronic obstructive pulmonary disease presented with new swelling in the neck and face. Physical examination was notable for massive subcutaneous emphysema as the cause of the swelling, which extended from the patient’s trunk and neck onto his face (Picture A). A CT scan showed extensive subcutaneous emphysema throughout the neck and thorax as well as a pneumomediastinum (Picture B, C). A pleural-cutaneous fistula was observed (arrow), which was likely the cause of the subcutaneous emphysema. There was a small left pneumothorax occupying approximately 10% of the hemithorax. There was no definitive communication between the pleural space and mediastinum, and the pneumomediastinum likely originated from the extensive subcutaneous air. Chest tube insertion and small subcutaneous incisions in the chest resolved the pneumothorax and subcutaneous emphysema. Spontaneous pneumomediastinum is associated with a relatively benign clinical course, and diagnostic testing to determine the pathologic cause yields little clinically relevant information (1).