Primary cerebral lymphoma: a study of 47 cases probed for Epstein-Barr virus genome.

To determine the prevalence of Epstein-Barr virus genome in primary cerebral lymphomas occurring in the absence of immune suppression. Forty eight consecutive patients with lymphomas restricted to the central nervous system were identified, all of whom had had neurosurgical biopsies performed at the National Hospitals for Neurology and Neurosurgery, London. Only five patients had some form of underlying immune deficiency; 43 were apparently normal. The tumours were studied with immunohistochemical markers and by in situ hybridisation, using a biotinylated probe to the internal repeat region of Epstein-Barr virus. All the lymphomas were B cell in origin. Tumours from the five immunosuppressed patients all showed hybridisation, as did two of the "spontaneous" tumours. This is the largest series of cerebral lymphomas so far probed for Epstein-Barr virus genome: as more are examined, it is suggested that a small proportion of the tumours from immunocompetent patients will also contain the virus.