Primary cardiac tumors are a rare set of benign and malignant neoplasms found in the heart or pericardium. We describe a patient presenting with nonspecific symptoms and ultimately diagnosed with primary cardiac non-Hodgkin's lymphoma (PCL). Our patient had extensive tumor in the right ventricle, which extended into the right atrium and right ventricular outflow tract. The tumor also encased the right coronary artery, which manifested as ischemic changes on EKG and cardiac MRI. The patient was treated with chemotherapy and achieved complete remission, with dramatic and full resolution of the mass on repeat echocardiography in nine weeks. More studies are needed to understand the optimal management and prognosis of patients with PCL.