TRENDS IN PRIMARY CEREBRAL LYMPHOMA

Primary non-Hodgkin lymphoma of the brain is rare, representing only 1 % of all non-Hodgkin lymphomas (NHLs), but its incidence has been incr easing rapidly in south-east England since 1985. Among 17,322 cases of NHL registered during the 18 year period 1973-90, there were 210 case s of primary cerebral NHL, of which 179 (86%) were diagnosed in the la st third of this period, 1985-90. This increase in cerebral lymphoma i s not adequately explained by improvements in the precision of diagnos is or by changes in disease coding or cancer registration practice. Wh ile there has also been a rapid increase in Kaposi sarcoma, neither im munosuppression acquired through HIV infection nor the overall trend i n non-Hodgkin lymphoma can satisfactorily explain the recent increase in cerebral lymphoma, which affects all ages and both sexes similarly. Other possible causes for a true increase in cerebral lymphoma should be sought.