Epstein-Barr virus (EBV), Cytomegalovirus (CMV) and Human Herpesvirus 8 (HHV-8) occur as silent lifetime infections in the vast majority of people. But when there is immunosuppression they reactivate to cause disease. EBV replicates in B cells and is linked to several forms of malignant lymphoproliferative disease, with EBV-associated Burkitt’s lymphoma accounting for the majority of childhood malignancies in equatorial Africa.
Clinical data: The patient was a 27 year old woman presenting with first time seizures. She was known to be HIV positive with a CD4 count of 301/ul. She had undergone six months treatment for tuberculosis in the preceding year. CT brain showed a space occupying lesion thought to be compatible with a diagnosis of tuberculosis (TB) or toxoplasmosis. MRI scan showed a necrotic mass, indicating either an infective or a neoplastic lesion. She was treated with steroids and anti-tuberculous drugs but died 10 days after admission.
Macroscopically: At post mortem the brain showed a partly necrotic mass in the right hemisphere, with multiple shifts. Sections of the brain show an infiltrating mass lesion primarily involving the basal ganglia on the right, with gross expansion and resultant left shift. Tumor has invaded the ventricular system and is growing on the ependymal surfaces of the inferior horns
MRI / Brain overlay:
Microscopically: Microscopy showed malignant lymphoid cells, and the tumour was characterised as a large B cell non-Hodgkin's lymphoma.
Comment: Primary CNS lymphoma is an important malignancy in HIV infected patients, and > 90% of these lymphomas are EBV positive. EBV infection and most of the mutations that precede malignant transformation occur before the B-lymphocyte invades the CNS.