Thoracic aortic aneurysm (TAA) is the ballooning of the upper aspect of the aorta above the diaphragm. We herein present a rare case of a massive ruptured TAA in a young male patient. A 30year-old male patient diagnosed with massive descending TAA with rupture Crawford Type I showing widening of the superior mediastinum with homogenous round opacity with regular smooth margins observed in left midzone silhouetting the aortic knuckle causing massive hemothorax with the passive collapse of the lung and mediastinal shift to the right. On color doppler it showed typical yin-yang sign.The patient underwent open chest repair with a graft. This case study demonstrated that TAA warrants an early diagnosis because the majority of patients exhibit no symptoms until the aorta ruptures or is dissected, which worsens patient morbidity and mortality. Furthermore, it prompts the necessity of early intervention like either endovascular stent placement or thoracotomy with grafting on the basis of CT angiography findings.