Primitive cardiac lymphoma (PCL) is a rare disease accounting for only 1-2% of primary cardiac tumors. Diffuse large B cell lymphoma is the most common type and shows a rapid progression with poor prognosis. The clinical presentation of PCL is nonspecific, and echocardiographic study is essential to the initial work-up. Magnetic resonance imaging and computed tomography scan are the methods of choice for the assessment of tumor extension. The definitive diagnosis is histopathology examination. Chemotherapy and radiotherapy represent the best treatment and should be started promptly after PCL diagnosis. We here report a case of PCL in a 59-year-old man complicated by pulmonary microembolism, atrial fibrillation and signs of right outflow tract obstruction.