Myocardial invasion by a neoplasm is a rare occurrence that can present identical signs and symptoms of acute coronary artery disease. We report a case of a 53-year-old man diagnosed with squamous cell lung carcinoma who presented with chest pain and ST-segment elevation on an electrocardiogram. He underwent emergent coronary angiography, which ruled out coronary artery obstruction. An echocardiogram followed by magnetic resonance imaging of the heart confirmed metastatic lung mass in the left ventricular wall. The direct compression of a metastatic tumor on a myocardial wall could lead to ST-segment elevation mimicking acute coronary syndrome. Clinicians should consider metastatic myocardial tumor as a possible cause of ST-segment elevation in patients with nonobstructive coronary arteries and lung carcinoma to prevent misdiagnosis and resultant delayed treatment.