Three, dynamic variants of ST segment elevations in a patient with osteosarcoma and cardiac metastasis.

In the right clinical setting, ST segment elevation (STE) on electrocardiogram (ECG) is most concerning for acute injury due to transmural myocardial ischemia. This frequently points to significant epicardial coronary artery disease, mandating emergent cardiac intervention. In rare cases, cardiac metastases may cause transient STE. We present a case of a 28-year-old male patient with metastatic osteosarcoma with STE in three different ECG territories over ten months. Several transient, dynamic patterns of STE were noted: anteroseptal leads concerning for acute injury with reciprocal ST depressions in inferior leads, lateral leads, inferior leads with reciprocal ST depression in lateral leads, followed by STE again in lateral leads. Given the patient's young age, absence of cardiac history or symptoms, personal preference, bleeding risk, and cancer prognosis, cardiac catheterization was never pursued. We present this case to remind providers to include metastatic cancer in the differential diagnosis of STE on ECG, and that these changes can be dynamic.