In December 2010, a 16 years-old man was admitted to a local hospital for complaints of chest pain, dyspnea, and neck pain presenting after spasm coughing. His medical history was unremarkable. Chest X-Ray and CT scan diagnosed the presence of pneumomediastinum without signs of pneumothorax and/or pleural effusion (Figure 1A). Thus, the patient was transferred to our hospital for diagnosis and treatment. Bronchosopic was attempted, but no endotracheal lesions were found. Gastrografin swallow excluded any esophageal perforation. Thus, the diagnosis of SPM was made. Medical treatment was done (reassurance, bed rest, oxygen, analgesic, and antibiotic therapy) with gradual improvement of clinical condition. Chest CT scan performed after 9 days, showed the complete disappearance of pneumomediastinum with no evidence of bullae (Figure 1B).

SPM was firstly described by Louis Hamman in 1939 (1). It is defined as the presence of interstitial air in the mediastinum without any apparent precipitating factor (2). Alveolar rupture leads to the accumulation of air in the interstitium that circulates centripetally through the venous sheats to the hilum and mediastinum (3). This occurs because the pressure in the mediastinum is lower than that of lung periphery. The most common symptoms are chest pain, dyspnea, and neck pain as observed in our case. If chest X-ray is negative, chest CT scan should be performed because up to 30% of patients with SPM have normal chest –X-ray as reported by Kaneki (4); yet, chest CT is useful to exclude undiagnosed chest pathologies. SPM is a benign condition that generally resolves with medical treatment (5,6). In our experience, we have observed five cases of SPM, of which one occurred just following extubation in a patient undergoing elective breast reduction for gynecomastasia (7). Our experience confirms the previously reported benign nature of this condition.