A 27-year-old man with episodes of hemoptysis for the past 12 h and left-sided chest dull pain without apparent cause for 2 months was referred to the emergency department. The amount of hemoptysis was approximately 200 ml, with no dizziness, tachycardia and hypotension. Initial physical examination revealed decreased breath sounds with crackles on the left side, and the chest pain was not related to breathing. Additionally, the patient had symptoms of hypoxemia and tachypnea, indicating a potential respiratory or cardiovascular condition. Troponin T and brain natriuretic peptide levels were elevated at 313.8 (reference range: 0-14 ng/L) and 506 (reference range: <88 ng/L) ng/L, respectively, while other laboratory parameters were within normal limits. The patient had no previous medical history of tuberculosis, bronchiectasis, or chest trauma, and denied any prior occurrence of Kawasaki disease or chronic inflammatory disorders. The patient initially sought medical attention at a local hospital where a CT scan was performed and was diagnosed with "pneumonia" 2 months ago. However, despite being discharged after a 9-day hospital stay, the patient continued to experience persistent chest pain symptoms.
The patient was admitted for further investigation due to the unclear cause of hemoptysis and chest pain. Chest x-ray (Figure 1A) showed an enlarged left cardiac silhouette with a conspicuous bulge encroaching on the left upper-middle lung field. In addition, bronchoscopy (Figure 1B) detected fresh blood in the left upper lobe bronchus, however, the definitive bleeding source was not identified. Subsequently, thoracic MRI with a T1W1 sequence (Figure 1C) demonstrated that the heterogeneous mass was essentially caused by active bleeding, and the possible diagnosis of a mediastinal tumor was excluded. Meanwhile, coronary CT angiography (Figures 1D,E) revealed a giant suspicious left coronary artery aneurysm (37 mm x 23 mm) wrapped in a large mediastinal mass (103 mm x 75 mm), which extended to the left chest wall and infiltrated the lung lobe. Furthermore, coronary angiography (Figure 1F; Supplementary Video S1) confirmed a saccular CAA originating from the middle portion of the left anterior descending artery. Based on these findings, the potential cause of hemoptysis was considered to be CAA rupturing into the left pulmonary parenchyma. The next day, the patient underwent emergency surgery due to the concern of a potentially life-threatening massive bleeding or acute myocardial infarction caused by the complete rupture of the coronary artery aneurysm. Preoperative transesophageal echocardiography showed a pericardial mass with normal cardiac function. During the median sternotomy, the pericardium prominently protrudes to the left, thereby presenting an ill-defined margin with pleura. After the removal of the limited thrombi eroding the left pleura densely and adhering to the left upper lung, a large pseudoaneurysm arising from a ruptured left CAA was identified (Figure 2A; Supplementary Video S2). The aneurysmal sac was resected, and a saphenous vein graft was used to bypass the distal left anterior descending artery (Figure 2B). The patient recovered uneventfully with cessation of hemoptysis, and predischarge CTA 9 days after surgery showed the disappearance of the left CAA (Figure 2C).