Cardiac malignant lymphoma in severe combine immunodeficient mice

Extranodal malignant lymphomas are known to occur with increased frequency in patients with human immunodeficiency virus infection. Although cardiac malignant lymphomas are rare, recently an increasing number of patients with acquired immune deficiency syndrome (AIDS) and cardiac lymphoma have been reported. To clarify the relationship between AIDS and cardiac lymphomas, we used 60 severe combine immunodeficient (SCID) mice as animal models in whom five different types of human lymphoma cell lines were injected. Primary lymphomas at the site of cell line injection developed within 14-30 days in 58 mice. Cardiac malignant lymphoma was detected in 10 cases (17%), among which tumour was macroscopically evident in 2. Tumour was present on the pericardial aspects of the heart extending into the myocardium in most cases, but no intracavitary lesion was observed. In one case, obstructive features were marked near the root of the great vessels by direct pressure of the growth. This study indicates that lymphomas have a predilection to invade the heart in immunocompromised conditions.