Introduction: Spontaneous pneumomediastinum is a rare entity, predominantly described in young man. The association of acute dyspnea, chest pains and subcutaneous emphysema is usually reported.

Case report: We report the observation of a pneumomediastinum, fortuitously discovered in front of an isolated giant subcutaneous emphysema in a 59 year old man. The recent clinical history was only marked by the presence of intense and acute dental pains. Associated with a pneumoperitoneum, a retro-pneumoperitoneum, this clinical presentation is uncommon and differs from previous published case reports. Despite a complete evaluation of classical risk factors, its origin remains uncertain. However, the presence of huge dental injuries led to consider such local origin, facilitating air diffusion.

Conclusion: This case report allows to reconsider spontaneous pneumomediastinum entity and to propose additional physiopathological mechanisms. This original description underlines the interest to systematically perform dental examination in the presence of unexplained pneumomediastinum.