摘要： 目的  报告一例非典型脉络丛乳头状瘤患者临床表现和组织病理学特征，并复习相关文献。方法与结果  男性患儿，1 岁。主因跌倒后呕吐3 d 入院，体格检查均未见明显异常。CT 显示左侧侧脑室占位性病变，密度略增高，侧脑室扩张、脑积水；相邻区域部分脑组织水肿。术中可见肿瘤组织呈灰白色、质地不均匀，血供丰富，与脑室内脉络丛粘连。光学显微镜观察大部分肿瘤细胞围绕纤维血管呈轴心排列形成乳头状结构，肿瘤细胞无明显异型性；部分区域肿瘤细胞呈实性团块状及小片状生长结构，细胞密度增加，呈轻至中度异型，局灶性坏死；部分肿瘤细胞胞质嗜酸性，可见少量肿瘤巨细胞，偶见核分裂象，计数为2 个/10 HPF。免疫组织化学染色肿瘤细胞表达广谱细胞角蛋白、突触素、细胞角蛋白8/18、波形蛋白、平足蛋白，灶性表达整合酶作用子-1；但不表达S-100 蛋白、细胞角蛋白19、神经元核抗原、胶质纤维酸性蛋白、上皮膜抗原、嗜铬素A 及细胞角蛋白7 和20；Ki-67 抗原标记指数约为8%。手术后随访6 个月，肿瘤无复发。结论  非典型脉络丛乳头状瘤为发生于脑室系统、生物学行为介于良性与恶性之间的罕见肿瘤，婴幼儿高发，手术完整切除肿瘤后预后良好，偶有复发。

关键词: 脑肿瘤, 脉络丛肿瘤, 病理学, 乳头状瘤

Abstract: Objective To report a rare case of atypical choroid plexus papilloma and explore its clinical presentations and histopathological features, at the same time to take a review of relevant literature. Methods and Results A 1-year-old male patient presented with vomiting for 3 days after a sudden tumbling. Computed Tomography (CT) showed a space-occupying lesion located in the left lateral ventricle. The lesion was with slight hyper-intensity signal compared to the adjacent brain parenchyma. Left lateral ventricle was enlarged and hydrocephalus was visible. Besides, edema occured in adjacent cerebral tissues. The surgical operation was performed under general anesthesia. During the operation, the tumor tissue was in heterogeneous consistency and rich blood supply, showing grey-white color, and attached to the choroid plexus. Microscopically, most tumor cells grew around the fibrovascular axis forming papillary pattern and showed no obvious atypia. However, in some areas, solid and sheet-like patterns were identified. Within these areas, increased cell density, mild to moderate cellular atypia and focal necrosis were appreciated. Some cells with acidophilic cytoplasm, few giant tumor cells and accidental mitosis were also seen, and the counting of mitosis was 2/10 HPF. Immunohistochemistry showed positive expression of pancytokeratin (PCK), synaptophysin (Syn), cytokeratin (CK)8/18, vimentin (Vim) and podoplanin (D2-40) in tumor cells. Integrase interactor-1 (INI-1) were also positively and focally expressed. The Ki-67 labeling index of tumor cells was 8％ . S-100 protein, CK19, neuronal nuclei (Neu-N), glial fibrillary acidic protein (GFAP), epithelial membrane antigen (EMA), chromogranin A (CgA), CK7 and CK20 were negatively stained. The patient was followed up for 6 months after operation and no recurrence was found. Conclusion Atypical choroid plexus papilloma, the biological behavior of which is between benignancy and malignancy, is one of the rare tumors of central nervous system that occurs in the ventricular system. The incidence is low. It often occurs in the early childhood with atypical histopathological features. Follow up is suggested although patients with complete resection usually have a good long-term prognosis.

Key words: Brain neoplasms, Choroid plexus neoplasms, Pathology, Papilloma