Primary central nervous system lymphoma of T-cell origin: description of two cases and review of the literature.

Primary lymphomas of the central nervous system (PLCNS) of T-cell lineage are unusual. It has been suggested that T-cell PLCNS, compared to those of B-cell origin, present some differences in relation to age of presentation, gender, location of the tumor and survival. We describe two cases with T-cell PLCNS and review 22 parenchymatous T-cell PLCNS reported in the English literature. Age, gender and survival of the whole series of 24 T-cell PLCNS did not differ from that reported in large series of PLCNS where the great majority were of B-cell origin. In contrast, a location in the posterior fossa was found in 54% of T-cell PLCNS, whereas this location ranged from 12 go 29% in series of, mostly B-cell, PLCNS. T-cell PLCNS had a higher frequency (33%) of the histologic low grade small lymphocytic lymphoma than B-cell PLCNS (5%). Analysis of six T-cell PLCNS long-term survivors showed that half of them had low grade lymphomas. We conclude that T-cell PLCNS do not differ from those of B-cell origin in age of presentation or gender, but they have a preference to develop in the posterior fossa and a higher frequency of low grade histology which would probably explain the longer survival in some patients.