ST-Segment Elevation Caused by Lung Cancer Mimicking STEMI

Figures

• 

  Visual Summary. Diagnostic Pathway of Cancer Mimicking STEMI CT = computed tomography; cTn = cardiac troponin; ECHO = echocardiography; STEMI = ST-segment elevation myocardial infarction.

• 

  Figure 1. PET-CT Evidence of Disease Progression (A) Noncontrast phase demonstrating a large, heterogeneous mass positioned in close proximity to the myocardium (red asterisk). (B) The hypermetabolic nature of this mediastinal mass is revealed with direct invasion into the pericardium. LV = left ventricle; PET-CT = positron emission tomography–computed tomography.

• 

  Figure 2. Admission Electrocardiogram Mimicking STEMI The ECG performed in the emergency department shows diffuse ST-segment elevation in the anterolateral leads (V1-V6, I, aVL) with diffuse PR depression. While these findings initially led to a presumptive diagnosis of a STEMI, this trace represents a “pseudo-STEMI” pattern caused by direct tumor-related myocardial involvement. ECG = electrocardiogram; STEMI = ST-segment elevation myocardial infarction.

• 

  Figure 3. Transthoracic Echocardiographic Assessment of the Cardiac Mass Echocardiography 4-chamber view reveals a focal area of myocardial thickening and regional hypokinesis in the anterolateral wall. A distinct, adherent, and mobile echogenic mass is visualized externally compressing the anterolateral myocardium (red asterisk). Notably, there is no associated pericardial effusion, which helped differentiate this mass effect from acute inflammatory pericarditis or hemopericardium.

• 

  Figure 4. Cardiac Computed Tomography Demonstrating Mechanical Compression Multidetector cardiac CT scan confirms the presence of a heterogeneous anterior mediastinal mass invading the pericardial space (red asterisk). The mass exerts significant mechanical pressure on the anterolateral myocardium and is in direct contact with the LAD and the LIMA bypass graft. These anatomical details confirm that the ST-segment changes were likely due to external compression and direct infiltration rather than acute coronary artery occlusion. CT = computed tomography; LAD = left anterior descending artery; LIMA = left internal mammary artery.

• 

  Figure 5. Admission Electrocardiogram The initial ECG demonstrates ST-segment elevation in leads V1 through V3 without evident reciprocal changes in the inferior leads. Notable T-wave inversion is present in lead III. These findings were carefully evaluated to differentiate between primary cardiac ischemia and secondary ST-segment changes related to noncardiac pathology. ECG = electrocardiogram.

• 

  Figure 6. Initial Chest Radiograph in the Emergency Department The baseline chest radiograph obtained upon presentation reveals significant mediastinal widening. This radiographic finding prompted further diagnostic work-up to evaluate for a mediastinal mass or vascular abnormalities, given the patient's presenting symptoms and electrocardiographic findings.

• 

  Figure 7. Contrast-Enhanced Computed Tomography Angiography Findings The CTA demonstrates a large, heterogeneous mass within the left upper lobe. The lesion is in direct anatomical contact with the right ventricular outflow tract and left pulmonary artery; however, there is no evidence of vascular invasion or significant luminal narrowing. CTA = computed tomography angiography; LPA = left pulmonary artery; MPA = main pulmonary artery.

• 

  Figure 8. PET-CT Imaging Findings Integrated 3-dimensional PET-CT imaging shows a large, solid mass located in the left upper lobe of the lung. The lesion demonstrates intense fluorodeoxyglucose (FDG) uptake, consistent with a highly metabolically active malignancy, without signs of macroscopic direct invasion to the pericardium or myocardium. AO = aorta; LPA = left pulmonary artery; MPA = main pulmonary artery; PET-CT = positron emission tomography–computed tomography; RV = right ventricle; SVC = superior vena cava.

• 

  Figure 9. PET-CT Follow-Up At the end of the treatment course, a follow-up PET-CT scan was performed, showing low-grade FDG uptake associated with consolidation (arrow) without signs of disease progression based on the follow-up evaluation. FDG = fluorodeoxyglucose; LPA = left pulmonary artery; MPA = main pulmonary artery; PET-CT = positron emission tomography–computed tomography.

• 

  Figure 10. Follow-Up Electrocardiogram After Chemotherapy Initiation A subsequent ECG performed during the course of treatment shows complete resolution of the ST-segment elevation in leads V1-V3. This electrophysiological improvement correlates with the significant reduction in tumor volume observed on follow-up imaging, suggesting that the initial changes were associated with the primary lung lesion. ECG = electrocardiogram.