原发性中枢神经系统淋巴瘤临床少见 ,约占颅内肿瘤的0 .5 %～ 1.2 % [1] ,文献报道在原发性中枢神经系统淋巴瘤的病例中 ,仅累及脑膜者占 6 .5 %～ 7.6 % [2 ] 。由于本病的临床表现及影像学改变缺乏特异性 ,临床诊断非常困难。我们于 1997年 7月收治 1例被误诊为多发性硬化的 Primary central nervous system lymphoma is rare, accounting for 0.5% ~ 1.2% of intracranial tumors [1]. It has been reported in the literature that in patients with primary central nervous system lymphoma, only meningeal involvement accounts for 6%. 5% to 7.6% [2]. Due to the lack of specificity of the clinical manifestations and imaging changes of the disease, clinical diagnosis is very difficult. One patient we received in July 1997 was misdiagnosed as multiple sclerosis