B-cell nature malignant lymphoma probably caused by EB-virus infection.

In cells in a haemopericardium associated with a B-cell malignant lymphoma, immature herpes type virus particles were found by electron microscopy. Epstein-Barr virus associated nuclear antigen (EBNA) and virus capsid antigen (VCA) were also found, both in the tumor cells, in the bloody pericardial fluid and in cultivated cells. Serological studies revealed high anti-toxoplasma antibody levels both in the pericardial fluid and in serum. Both EB virus and toxoplasma infections are assumed to have played an important role on the pathogenesis of the present case.