Primary Cardiac Lymphoma (PCL) is a very rare condition accounts for 2% of all primary cardiac tumours. This is a case report of a 76 year old male patient with shortness of breath, cough and pyrexia of unknown origin for 2 months. In the initial diagnostic workup, echocardiography revealed aortic and mitral regurgitation with no pericardial effusion. With the development of right sided pleural effusion about one month after the initial presentation, ultrasound scan guided pleural fluid aspiration performed. Pleural fluid culture revealed no bacterial growth. Second echocardiography showed no flow in the Superior Vena Cava (SVC) and suspected of a thrombus. Contrast enhanced Computed Tomography scan of the chest demonstrated a mass lesion in the right heart and distal inferior vena cava (IVC). The lesion was compressing the SVC without complete obstruction. The pericardium was intact with no pericardial effusion. No mediastinal lymphadenopathy identified. Initial differential diagnosis was leiomyosarcoma of the distal IVC extending in to the right heart. As there was no pericardial involvement, possibility of lymphoma was made as a remote cause. Subsequently digital subtraction angiography guided biopsy performed from the mass in the distal IVC and right atrium. Diffuse lymphoma was confirmed on histology. As there were no Hodgkin cells in the sample, probable diagnosis of Non-Hodgkin's lymphoma was made. Subsequently patient died due to cardiovascular compromise before starting specific therapy.