Primary cardiac lymphoma is classically defined as an extranodal non-Hodgkin's lymphoma exclusively located in the heart and/or pericardium. However, over the last few years, this definition has been extended to include other localizations on condition that these are clearly less important then a cardiac site, that must remain the first, during the illness course, and the most important for its entity. PCL is extremely rare in immunocompetent patients, accounting for 1.3% of all cardiac tumours and 0.5% of all extranodal lymphomas, but it has been encountered with increasing frequency in patients with AIDS or other severe immunodepressive syndromes. PCL is difficult to diagnose, especially during the early stage of the disease, because of its non-specific clinical manifestations, the limited possibility of using non-invasive diagnostic techniques, and difficulties or delays in applying invasive methods. The malignancy of its histotypes and its delicate location are responsible for its rapid and frequently unfavourable evolution. Successful treatment, which is mainly based on anthracycline-containing polychemotherapies, is heavily dependent on an early diagnosis. After a general review of the literature, the authors describe the clinical case of a patient with a PCL that had a secondary central nervous system location, treated with polychemotherapy and autologous peripheral blood stem cell transplantation. Emphasis is placed on the fact that it is more difficult to eradicate the disease from the central nervous system than from the heart.