Recurrent spontaneous subcutaneous emphysema of unknown origin: A case report with literature review

Introduction: Subcutaneous emphysema caused by a surgical operation is known as surgical emphysema, and if the cause is unknown, it is known as spontaneous subcutaneous emphysema. The current study aims to report a rare case of recurrent spontaneous SE of unknown origin. Case report: A 27-year-old male patient presented with swelling of the chest, neck, and face that had started 20 days prior. There was crepitation on palpation. Pulmonary function tests were normal. Laryngoscopy showed a normal larynx. Bronchoscopy showed a normal bronchial tree except for some redness in the trachea and left main bronchus. Computed tomography of the chest with contrast showed subcutaneous emphysema in the anterior chest and lower neck. The patient reported a similar condition 3 years prior resulting in swelling of the upper left chest with an associated pneumothorax that was treated with tube thoracostomy. Workup including VATS was done to find the underlying cause but no cause was found. Discussion: The pathogenesis is the same as in the most cases. Air that is driven into the interstitial tissues around the pulmonary vasculature gradually moves back toward the lung's hilum, resulting in pneumomediastinum. The air gradually spreads to the soft tissues of the neck, face, chest, and limbs, resulting in widespread subcutaneous emphysema. Conclusion: Spontaneous subcutaneous emphysema without known origin is a rare condition that may resolve by conservative treatment.