We report a 25-year old immunocompetent woman with a high grade primary non-Hodgkin's lymphoma of the central nervous system (PNHL-CNS) in whom the administration of dexamethasone alone during three months produced a complete clinical and radiological response lasting over four years. If complete remission of PNHL-CNS induced by glucocorticoids are well known, the opportunity to observe glucocorticoid-induced remission for a long period of time without radio- and chemotherapy is rare. Only nine other cases of PNHL-CNS with complete remission induced by glucocorticoids lasting from 6 to 60 months, were found in the literature and are summarized here. Duration of glucocorticoids therapeutic effect in PNHL-CNS is probably underestimated. Glucocorticoids cannot be recommended as sole initial treatment for PNHL-CNS. However, we suggest standard therapies to be delayed in those patients responding completely to glucocorticoids where radio- and chemotherapy should be contraindicated (kidney, liver, bone marrow failure, pregnancy).