A 73-year-old man who had been transferred to our emergency room due to sudden chest pain was diagnosed with ST-segment elevation myocardial infarction (STEMI). Primary percutaneous coronary intervention was performed. A long, white object which looked like a parasitic worm was retrieved via intracoronary aspiration and revascularization was successfully completed. Contrast computed tomography revealed a huge 7×6 cm mass in the right upper pulmonary lobe with direct pulmonary vein invasion. Histopathologic examination of the aspirated coronary object revealed pleomorphic lung carcinoma. This is an unusual case of STEMI caused by lung tumor embolization via direct pulmonary vein invasion to the left side of the heart.