目的　分析 4例我院收治的类似肿瘤样表现的不明原因脑炎的临床特点 ,以期达到对本病的早期认识。方法　临床表现及病理学结果回顾性分析。结果　该脑炎的主要临床表现为 :发病年龄 2 0～ 6 0岁 ,发病时间 2 0 0 2年 6月至 2 0 0 3年 4月 ,无明显季节性和传染性 ,亚急性起病 ,可伴发热或无发热 ,逐渐进展的颅内压升高 ,脱水后可暂时好转。意识障碍较轻 ,3例伴精神症状但抽搐不明显 ,2例影像学可见脑实质大面积病变 (白质为主 ) ,并可累及脑干等部位。病理活检可找到类病毒颗粒 ,但抗病毒治疗效果较差。结论　对发热伴亚急性逐渐进展的颅内压升高的患者 ,结合影像学结果诊断时 ,应考虑本病的可能性。 Objective To analyze the clinical features of 4 cases of unexplained encephalitis treated in our hospital with similar tumor appearance in order to reach the early recognition of this disease. Methods The clinical manifestations and pathological findings were retrospectively analyzed. Results The main clinical manifestations of the encephalitis were as follows: the age of onset was 20 ~ 60 years old, the onset time was from June 2002 to April 2003, no obvious seasonal and infectious, subacute onset, Can be associated with fever or no fever, progressive increase in intracranial pressure, dehydration can be temporarily improved. The disturbance of consciousness was mild. Three patients had psychotic symptoms but convulsions were insignificant. Two cases of brain parenchyma lesions (white matter-based lesions) were seen in 2 cases and involved brain stem and other parts. Pathological biopsy can find virus-like particles, but the anti-virus treatment is less effective. Conclusions For patients with fever and subacute progressive intracranial pressure, the possibility of this disease should be considered when combined with imaging findings.