Primary cardiac lymphoma (PCL) is a rare neoplasm, the majority of cases of which are non-Hodgkin's, diffuse large B-cell (DLBCL). We report the first case of an adult with PCL B-cell lymphoblastic lymphoma whose disease evolution was grim. A 52-year-old male reported dyspnea and facial swelling lasting for 4 months and upon a physical examination he presented bradycardia, jugular venous engorgement, and hypophonesis of cardiac sounds. An electrocardiography (Echo) revealed a right atrial mass and nodules at the pericardium. The patient was treated with R-Hyper-CVAD (rituximab plus cyclophosphamide, vincristine, doxorubicin, and dexamethasone) and presented very short remission. At this time, we used R-ICE (rituximab plus ifosfamide, carboplatin, and etoposide) chemotherapy and the patient underwent complete remission after two courses and received autologous bone marrow transplantation (auto-BMT). After 75 days of follow-up, the patient reported dyspnea and a new Echo showed a recurrence of the disease. The patient died due to cardiac failure. PCL is a rare disease with an unfavorable prognosis and a prompt diagnosis and treatment are fundamental to survival. We believe that more intensive therapies, such as auto-BMT, should be considered as a first treatment option.