Occult primary cardiac lymphomas causing unexpected/sudden death or acute heart failure

Three cases of unexpected/sudden death (N = 2) or acute heart failure (N = 1) were investigated in our centre. The first patient died unexpectedly after surgery for cardiac tamponade and constrictive pericarditis; at autopsy, gross features mimicked a pericardial mesothelioma. The second patient died suddenly after recovering from a respiratory insufficiency episode; autopsy revealed an epicardial mass encircling the right coronary artery. The third patient presenting symptoms mimicked a fulminant myocarditis and she underwent endomyocardial biopsy. In all cases, histology disclosed a diffuse large B cell non-Hodgkin lymphoma, localized to the pericardium together with the right ventricle and the conduction system, to the epicardium and the right coronary artery or to the myocardium, respectively. Histology was crucial for the diagnosis, the atypical presentation favouring other diagnostic hypotheses. Although primary cardiac lymphoma is uncommon and usually shows a sub-acute onset, it may also cause unexpected/sudden death or acute heart failure.