Abstract: Objective  To study the clinical and pathological features of central nervous system (CNS) cryptococcosis.  Methods and Results  A 26-year-old male patient presented with headache and fever. Glucose, chloride and protein level was abnormal in cerebrospinal fluid (CSF) examination, but the pathogen was not found. MRI showed patchy abnormal signal at right cerebellum, the fourth ventricle and posterior horn of lateral ventricle. During the operation, cystic lesions located in right temporal lobe and grayish black choroid plexus were found, and temporal lobe lesions and degeneration of choroid plexus were partially resected. After operation, 3 pieces of greyish green tissues were resected, measuring 1.50 cm × 0.60 cm × 0.50 cm. Optical microscopic examination found a large number of birefractive oval and (or) circular cryptococcus in the brain tissue and choroid plexus, with foreign body giant cell reaction and lymphocytic infiltration. Cryptococcus could also be seen in giant cells, and spore formation was found in part of them. Periodic acid-Schiff (PAS) and periodic acid silver methenamine (PASM) staining showed positive expression of cryptococcus. Conclusion  Cryptococcosis is a common CNS fungal infection caused by cryptococcus neoformans. A large number of cryptococcus neoformans in brain tissue or lacuna is the characteristic pathological manifestation, and positive expression in PAS and PASM staining can be shown in CSF.

Key words: Cryptococcosis, Meningoencephalitis, Immunohistochemistry, Pathology

摘要： 目的 探讨中枢神经系统隐球菌病临床病理学特点。方法与结果 男性患者，26 岁。以头痛、发热发病，多次脑脊液检查蛋白定量、葡萄糖和氯化物异常但未发现明确的病原菌生长。MRI 检查显示右侧小脑及第四脑室、侧脑室后角呈片状异常信号。外科手术探查可见右侧颞叶囊性变，脉络丛呈灰黑色，光学显微镜观察可见大量呈双折光之卵圆形和（或）圆形隐球菌菌体，伴异物巨细胞反应及淋巴细胞浸润，巨细胞中亦可见隐球菌菌体，部分菌体似有芽孢生成。高碘酸-雪夫（PAS）和六胺银（PASM）染色隐球菌呈阳性反应，明确诊断为脑膜脑炎型隐球菌病。结论 隐球菌病为中枢神经系统常见真菌感染性疾病，由新型隐球菌致病，以脑组织或相应脑腔隙内出现大量隐球菌菌体为其特征性病理改变，脑脊液特殊染色（PAS、PASM 染色）呈阳性反应。

关键词: 隐球菌病, 脑膜脑炎, 免疫组织化学, 病理学