Primary cardiac lymphoma (PCL) is a very rare neoplasm, which involves only the heart and pericardium without evidence of extracardiac involvement. We herein report a unique case of a 64-year-old man presenting with increasing exertional dyspnea, worsening orthopnea, oxygen desaturation and upper body swelling. Subsequent investigations revealed a large obstructive right atrial (RA) tumor. Due to the patient’s deteriorating clinical condition, urgent surgical removal of the tumor was planned and successfully performed. Histopathological findings were consistent with the diagnosis of primary cardiac lymphoma. The patient subsequently completed his chemotherapy cycles and is currently in remission.