Spontaneous pneumomediastinum and COVID-19 pneumonia: report of three cases with emphasis on CT imaging.

Spontaneous pneumomediastinum is a rare complication of coronavirus disease 2019. The published literature consists mainly of case reports and small case series. There are still many questions regarding the pathogenesis, the prognostic significance and the implications on patient management. In our hospital, 3 coronavirus disease 2019 patients developed spontaneous pneumomediastinum: 1 on admission at the emergency department and the other 2 during hospitalization. In this study we describe their clinical course and computed tomography (CT) findings. All of them had severe disease according to the total severity score on admission CT. The management of pneumomediastinum was conservative and follow-up CT showed resolution in all patients. As the correlation between extension of parenchymal lung lesions and development of pneumomediastinum is still under investigation, we highlight the importance of reporting the severity score on chest CT in order to obtain more comparable results between different studies. Furthermore, in this tragic circumstance we also had the opportunity to familiarize ourselves with the otherwise uncommon occurrence of air along the bronchovascular sheaths (Macklin effect) and evaluate the ability of CT to detect it.