Cardiac localization of non-Hodgkin's lymphoma: two case reports and review of the literature.

Secondary non-Hodgkin's lymphoma of the heart (SNHLH) are more frequent than primitive non-Hodgkin's lymphoma and represent the third most common malignant tumour of the heart in autopsy studies. Cardiac involvement usually occurs as a late manifestation in patients with disseminated disease. Initial cardiac lymphoma, defined as cardiac involvement at initial diagnosis with concomitant extracardiac localizations, have nevertheless been reported in approximately 42 cases. The present paper concerns two patients with non-Hodgkin's B-cell lymphoma where cardiac involvement occurring 3 and 6 years after initial diagnosis constituted the unique site of relapse. These cases differ from previous reports of the literature by the predominance of extranodal localizations at initial diagnosis and the late onset of cardiac involvement. Clinical and radiological findings were otherwise in accordance with those usually described in such patients. Transthoracic echocardiography revealed the cardiac tumour in the first case, but in the second case transoesophageal echocardiography and magnetic resonance imaging (MRI) were required to demonstrate its presence. As in most reports, the site of tumour involvement was the right cardiac cavity and histology showed high grade B-cell non-Hodgkin's lymphoma. Polychemotherapy, associated with radiotherapy in the second case, led to partial or complete remission of the cardiac tumour without recurrence within the months of follow-up, although both patients died of their disease within one year.