OBJECTIVETo investigate the characteristics, treatment and outcome of patients with primary central nervous system lymphoma （PCNSL）.

METHODSA total of 37 patients with PCNSL treated in Peking Union Medical College Hospital from June 1999 to June 2012 were enrolled into this retrospective study. The clinical characteristics, results of treatment and prognostic factors were analyzed.

RESULTSThe median age of 37 patients with PCNSL at diagnosis was 57 years（range 17 to 78 years） with a male to female ratio of 2.7:1. The symptoms or signs of elevated intracranial pressure and cognitive dysfunction were the most common initial manifestations. The median time period between onset of symptoms and diagnosis was 1.5 months. The majority of lesions were located in the cerebral hemisphere. At a median follow-up of 50 months, the median overall survival for all treated patients was 36.0 months （95% CI 21.7-50.3 months）, with a progression-free survival of 18.0 months（95% CI 9.1-26.9 months）. The 3-year cumulative survival rate was 46.9%. Compared to chemotherapy alone, combined-modality regimens which did not improve outcome were associated with a greater risk of neurotoxicity.

CONCLUSIONThe prognosis of PCNSL was still poor, and the optimal treatment strategy for these patients should be explored in the future clinical trials.