自發性縱膈腔肺氣腫常以胸痛表現，好發於年輕男性，危險因子包括之前有肺部疾病和Valsalva maneuver。理學檢查可發現皮下氣種，大多數病患可藉由胸部X 光診斷，是否再安排電腦斷層排除其他致命性疾病則眾說紛紜。它是一種良性、自癒、且很少復發的疾病，對於藥物治療的反應良好。在此，我們報告ㄧ個男性29 歲以急性胸痛就醫，心電圖有廣泛性的ST 節段上升，並討論和自發性食道破裂與急性冠心症等急症的鑑別診斷和回顧文獻所發現的心電圖異常。

Spontaneous pneumomediastinum is an uncommon disease presenting with the commonsymptom of chest pain and usually affects young males. The risk factors include preexisting lungdiseases and the Valsalva maneuver. Subcutaneous emphysema is the main physical finding.Diagnosis is made by chest radiography in most patients, but routine use of computed tomographyof the chest to exclude life-threatening conditions is controversial. Invasive procedures have beenperformed to exclude the fatal disorder of Boerhaave’s syndrome, although with little reporteddiagnostic value. Spontaneous pneumomediastinum is a benign, self-limited, rarely recurrententity which responses to conservative treatment well, requiring no hospitalization or aggressiveintervention in the absence of concomitant pneumothorax or severe underlying disease. Herein,we reported a 29-year-old man who presented with spontaneous pneumomediastinum and diffuseST-segment elevation on electrocardiography We also report the findings of a literature review ofcases of spontaneous pneumomediastinum.